I can relate to you 100%. I'm 19 and I only started embracing my curls recently, so I understand how hard is. I started getting my first relaxers at the age of 8 and got my last one when I was 18. When I was in my senior year of high school, I decided that I didn't want to relax my hair anymore. As I was transitioning (and dealing with the 2 different textures of hair) I got some comments made to me about how i needed to relax my hair, but I didn't care. The way I saw it was, at least I'm gonna have nice & healthy hair eventually unlike all of them.
I didn't do a BC either btw, because I've always had long hair that was down my back & that would've been too much for me. I did do 2 major hair cuts though. In February 2012 I cut my hair to my shoulders & in March 2013 I cut the rest of my relaxed hair off which ended up making my hair up to my shoulders again.
You're gonna have to be patient, and you need to have a lot of courage. Your hair isn't going to become healthy over night. Don't worry about what any of those people think about you. I know you're in high school, and that's hard to do, but you have to be brave & think of yourself. If you keep relaxing & straightening your hair, you're gonna lose your hair. Your hair can only take a certain amount of abuse. So first things first, STOP USING HEAT. No more straightening, blow drying, relaxers, nothing. Next, try doing a restorative mask on your to strengthen it a little. I like the one from Shea Moisture. Make sure you use leave-ins, and oils. You should really read the Curly Girl Handbook. It has so much info in there to help you! I really hope your journey goes well.
Sorry for such a long post btw, hahaha.