Reconnecting with a girl who disappeared

Before I start the story, you should know that I'm 23m, have never been in a real relationship, had sex or even kissed a girl. I feel like I am moderately handsome, I workout almost every day and I get a lot of looks from girls my age, but I am awkward as hell. In high school I was overly infatuated with a girl that resulted in me not even attempting to date for years, and I feel like I fell behind and now the thought of dating scares me to death.

A few years ago I took a fitness course at College A as an elective where I met a girl who seemed cool. I flirted with her and made her laugh a lot. The next semester she ran into me at the same time every week like clockwork and always made a point to smile or say hi. I decided that I was going to ask her out but then she never came by again, and I never saw her around the college. I tried to find her online to no avail.

I graduated then went to College B. A couple years passed and now I'm back in the city where College A is. While on LinkedIn one night, she happened to appear in my recommended connections. I added her and she added me back in less than 20 mins.

I am sure that she was into me back then and might still be now and I really want to ask her out. The problem is that I am somewhere in the top 10 most awkward people on the planet. I'm not sure how to initiate a conversation with her online. Would it be weird to go straight to admitting that I meant to ask her out back then? I really have a lot of questions running through my head, so if you guys could offer any advice I would really appreciate it.

Thanks,

Splat