Hi, boy. I understand your point. Our desire is the same. I was so much like you back then. I have wanted to wear a bra since I was ten but never had the chance and courage.
When I was in secondary school, I was more inspired to wear them at school, but I made them a secret and wore sports bras. I only wear a regular bra when I am at home. However, I still needed to be cautious, so my family members would miss me.
Only when I was a bit brave did I tell my closest sister I had already enjoyed the bra. She was a bit shocked, but later, she accepted me in those clothes and began to help me shop for them.
If you want to wear a bra at school, make it very top secret. If you can hide it, do it. If you think you can't. Just don't, or you will face a big scar in your life of being bullied if someone figures it out.
The safest place you can have been being just your home.