How do you know when you're attracted to someone?

Sorry if this is a bit long...

I met a guy online and we started talking via texts and emails for a couple weeks. We had a great connection so we decided to meet (safely of course) in person since we lived so close to one another. I just met him this week and we've hung out a twice with a third date coming up. He seems like a really nice, genuine guy, who makes me feel beautiful and I am comfortable around him. He has a good sense of humour and is smart. The problem is that I'm just not sure if I am physically attracted to him. I haven't dated in many years and so I'm not sure what I'm feeling or what I'm supposed to be feeling at such an early stage. We do hold hands sometimes, which feels a bit awkward at times but nice for the most part. I just can't picture myself kissing him or anything just yet. And he doesn't have the best sense of fashion. He's a bit of a nerdy guy and sometimes stutters when he's nervous too. I'm not one to judge anyone on their physical appearance so I shouldn't be judging him at all, but I can't help but notice these little things. My question is, how do you know when you're attracted to someone? Is it something that's supposed to be instant? Should I continue seeing this guy and wait a bit longer since it's only been a couple of days? Any advice would be greatly appreciated. Thanks.

Wow I know how you feel and what your sayin I was like that with my husband of 17 yrs now when we met i had the same feeling u do but things worked out and i looked past the flaws and fell in love with him and I am glad I did he is the best man I have ever had

Well as far as your question goes I like to think it's pretty instantaneous, but yes someone can be become more attractive overall and you can learn to like things about them and get comfortable with their physical attributes as time goes on. As far as things like holding hands being awkward I can't blame you if it's been a while, but if that lasts then that's a different story. You say it's only been a few days, so yes I would give it some more time. However as Britt said, if it's there it's there, like chemistry. In my personal experiences it's always been fairly instantaneous, but everyone is different and I would in no way discredit the fact that it can still happen. You might be noticing the little things because you've been "out of the game" for a while, and so maybe over that time you've developed an image or character that you envisioned dating when you went back to doing so, and so these little things are variances to what you had pictured, and maybe it'll just work itself out. I would keep going see how it goes for a little longer and then re-contemplate everything.