Am I Behind?

My sister and I are twins, both of us being fifteen. Just a few hours ago she lost her virginity, and through the past few months she’s been giving blow jobs and handjobs, her boyfriend has been fingering her and doing oral sex on her.

I, meanwhile, have only had one boyfriend, who broke up with me six months ago. And we never did anything nearly that extreme.

We’re the same age...should I be doing all this stuff? I can’t help feeling like I’m super behind. She’s always been a little cooler and a little ahead of me, and I’ve always been frustrated about it, but I definitely feel really confused about this one.