Remember me?

Is there etiquette involved in approaching someone you remember from your past in person? I saw this chick I used to hang out with in Junior High School, (we had a not sex relationship just knew her moslty from hanging out with her brothers but she was in all my classes growing up), this morning on the train and honestly I didn't even want to talk to her I just wanted to know if she was who I thought she was. But didn't know how to go about asking. Women these days find it weird for random guys to talk to them. They'd much rather you "friend" them on facebook and talk via text for days on end.

Anyway is there a proper way to say hey, remember me? From my persepctive my appearence from then to now has changed. I'm barely recognizable. I've put out like 60 pounds of muscle and or fat (real skinny scrawny kid in JHS) and had glasses (not anymore). So recognizing me is not easy. I remember every kid I went to JHS with. And this isn't the first time this has happened although it is the first time someone I thought I knew sat next to me on the train. So hello Theresa Palermo. Sorry I don't have facebook.