This was a big week in the life of my family: my older daughter Eliza has gone off to college.

In her case, she did a pre-program, where she went hiking in New Hampshire with a small group of other incoming freshmen. This step reminded me of how we did the “Separation” stage when she was starting pre-school.

During pre-school, she began the school-going experience by attending for a short day, I’d wait nearby with the other parents, and she and I got used to the idea of her going off to school by herself.

For this outdoor program, we sent her off, but it felt more like a return to summer camp. Before she left home, the focus was on “Do you have the right hiking gear?” not “Now you’re saying good-bye to our dog Barnaby for several months.” When I dropped her off with her backpack, we told each other, “See you next week.”

This hiking trip made the transition less abrupt. During that week, I told my husband, “I feel like I’m on the mezzanine level — in the mid-way point between two stages.” It was helpful to Eliza, because she got the chance to get to know a group of other students beforehand.

Then after a week, my husband, my younger daughter Eleanor, and I packed up the car to meet her. We spent the day unloading, unpacking, meeting Eliza’s roommate and her family, buying a trash can, and all the rest.

I can get very tightly wound in situations like this, so in the car on the trip up, I announced to my family, “I’m really going to try to stay calm. I know there will be ambiguous directions [a pet peeve of mine], and it’s going to be hot, and there will be a lot of waiting and frustrations, but I am going to stay calm.” (My mother is rightly always reminding me to stay calm.) I wanted this day to be a memorable, fun, serene good-bye day. I didn’t do a terrific job of staying calm, but I did a pretty good job of staying calm.

If there’s one thing I’ve learned about happiness, and about self-mastery, it’s to think in advance about the experience I want to have, the likely pitfalls, the challenges that always trip me up. By using the Strategy of Safeguards, I help myself avoid acting in ways that will cause me regret later.

It’s always odd, for me, when I’m going through an experience that I know will be a major life milestone. As we were waiting for Eliza to return from the hiking trip, I said to Eleanor, “I remember so well the day I moved into college. For all of us, we’ll remember this day. We’ll reminisce, ‘Remember Eliza’s first day?’” I had a similar thought when Eleanor came home from the hospital. A friend sent flowers, and I remember rocking Eleanor and thinking, “I have a baby who is such a newborn that the congratulatory flower arrangements are still fresh.” That happened more than twelve years ago.

Time is so strange, how events can seem so distant and yet so recent. Already, Move-in Day seems like part of the distant past. Of everything I’ve ever written, this one-minute video, The Years Are Short, is the thing that has resonated most with people. Now that little girl who rode the bus with me is off on her own.

In episode 125 of the “Happier” podcast, we talked about advice that listeners suggested for dealing with this family transition (also for packing–we got lots of great packing recommendations). The advice was great, and the most helpful suggestion came from the listener who said, “Remember, this is the end of something, but it’s also the beginning. You’ll have a new chapter in your family life, new favorite restaurants, and spots to visit, new memories. This chapter is short, so enjoy it.”

I’ve reminded myself of that helpful observation often, because of that, for me, addresses the heart of my mixed feelings about this time.

I’m thrilled for my daughter — she’s ready for this change, this experience will be terrific, she is so very fortunate to have this opportunity to get more education. And of course this change is a happy change  — while often when we deal with endings, it’s in the context of loss.

I’m sad because it’s the end of her childhood — of her being under our roof. Last week, I got a shock when I glanced into her room in the early morning: her door was open, her bed was made, and for a moment I panicked, where was she?

And even the extra space in our bathroom makes me a little sad. She shared a bathroom with my husband and me, and the removal of her products gives us a lot more room in the medicine cabinet. This change was gratifying to my simplicity-lover side, but it was also an unexpected visual reminder of her absence.

Speaking of echoes to pre-school separation, I keep reminding myself of the wise observation made by the nursery-school director, who as we went through “separation,” told us, “This is the first of many times that you will say good-bye to your child.”

We’ll see her soon. Visiting Day, Thanksgiving, and sheesh, I’ll be back in town for an event in less than three weeks! (I told her she didn’t have to attend, and she and I didn’t even need to see each other, if she thought it would be too unsettling to have me pop back into view.)

It won’t be the same, but while it’s the end of an era, it’s also the beginning of an era.

If you want to hear Eliza’s views, you can listen to her podcast “Eliza Starting at 16.” I certainly can’t wait for her next episode. We also did a Facebook Live broadcast together where viewers gave both of us advice for this big transition. Watch it here.

For me, it’s always difficult when something comes to the end. Even if I’m ready and happy for it to end, I always feel a sadness in the thought that a period of my life is over.

But then I remind myself, “No beginnings without endings. Growth brings change.”

Also, I remind myself, “Gratitude.” As always is the case, feelings of gratitude crowd out negative feelings. When I think about how very, very, very fortunate we are, that comforts me. And that steels me to handle my own feelings and to turn outward, to think about other people’s difficulties and challenges, and the problems of the world.

Have you grappled with this feeling — of dealing with the end of an era?