I don’t know if you have a self-esteem problem or if your problem is that you are comparing yourself to other people you know.
The fact is that people are on a sociability spectrum. Some people seem to be born sociable and chatty. On the other end of the continuum are people who are more introverted and more comfortable being alone or with a close friend or two. Anywhere on that spectrum is completely normal.
If you’d like to be around more people, and perhaps to build up your self-esteem, I’d suggest you get involved with volunteering at a charity that matters to you and where other young people give their time. When the focus is on the task, not on being Miss Congeniality, many people like yourself are more comfortable. Often working alongside others over time also leads to new friendships. Why don’t you give it a try?
I wish you well.