Apologizing to a girl (not dating)?

There's this girl that I have been friends with for a very long time, since preschool. We text each other as much as we can, but were not dating. I had this attraction towards her, and I thought she did with me. So back in grade school (I'm a sophomore and she's a junior in high school now) I was being real stupid so I went up to her and said she had big boobs. She just brushed it away. But last night, that came up in our conversation. She thought it was hilarious, and so did I looking back on it now. So whever i ask her an embarrassing question, I always ask that she won't be offended or embarrassed or mad at me. I've asked her a lot of embarrassing questions, but this one went to far. I told her that with her permission, I would want to see her boobs. I thought she would say yes becUse we have been best friends forever and it wouldnt be awkward. But she replied with 'gtg, bye.' I know that something was wrong, so I tried calling her but she wouldn't pick up. I knew from that moment I was screwed. I knew I messed up, and I knew that I sound like a pervert to her right now. She won't reply to my texts and calls, and I only see her once a week, and maybe less. How do I get our friendship back together again?