What the hell is going on with me?

Anonymous
I'm 28 and I've never been in a relationship. In fact, I've never been in love.
But something weird happened. There's a new waitress at my friend's restaurant. When I saw her I found her nice and cute. But that was all. Just like when I see any beautiful girl.
I went there again later. This time we chatted a little. Since then, I cannot stop thinking about her which is weird because I only saw her twice, I am not even able to recall her face. I remember I found her cute but I really don't remember what she looked like. I don't even know anything about her except her name and age. So I don't believe I fell in love. But NEVER have I ever been unable to stop thinking about a girl.
I am an introvert and suffer from extreme lack of confidence. I have difficulties going to new places, talking to strangers. I have never believed I could be good at something, or someone could actually like me and date me so I never bothered trying. And these problems were here with me my whole life.
I recently turned 28 and I started to realise a good portion of my life is gone and I haven't achieved anything, haven't met anyone, haven't really done anything. I never went to parties, hung out, dated women. You know, didn't do things normal people do. So I decided to start doing them now. Well, except dating. I still don't feel ready for that.
I am actually experiencing some early "midlife crisis".
But in the past few months I slowly started to become a little more normal. Started hanging out more. But I still lack confidence A LOT, so no dating.
My 28th birthday made me crave all the things I mentioned. I want to party, drink, have fun, I want to fucking live my life. I don't know what happened but now I regret being that shy introverted MF and hate myself for not trying to have fun before. Do you think this change could have something to do with me thinking about that girl all the time?

Guys and girls, what's wrong with me? Am I in love? Am I just getting old or WTF?
What the hell is going on with me?
3 Opinion