Ten is an average age for a young woman to start developing. That is not odd at all. I'd say, if anything you were possibly a year late or so as the majority in my experience has shown that females start puberty around late into age 8 or early into age 9. And no, you're not fully developed and you've not finished puberty at 18. I know it looks it and feels it but you've not.
Your values, morals and personality WILL change. Again, asking for posters age 25 and up. Do you remember when you were 18? Do you still believe in everything you did then? The correct answer is no. You see, mentality is purely based on maturity. Which is purely based on age. Your views continuously are changing.
Ten is actually really young; the "average" is including all of the obese people who bring down the number. I was overweight my entire life. That's why I started menstruating when I was 10. Weight is one of the main factors. Normally, people start developing around 12 and menstruate around 14.
Also, you don't study human psychology professionally. Maybe your morals changed from bad to good (hopefully, and not the other way around), but when your morals start off good and you hang around with the right crowd, your morals
will not change, and nei' will your values and personality. You might become less obnoxious or arrogant, but you aren't likely to turn into a downright bish if you hang around people with a good influence.
Maturity is not based on age. That's where you're wrong. Maturity is based on experiences and influences. Age has barely anything to do with it. You know what age measures? It measures how many experiences you've possibly had in your life that would
form your maturity. It isn't maturity itself! Someone who's 22 who probably have experienced someone who's 15, simply because they've lived 7 years longer -
however, someone who's 15 and has had a rough life and seen many things and experienced many different situations could be just as mature as someone who's 22 and took an extra 7 years to experience the same or similar situations.
That, my friend, is truth.