afraid of intimate relationships?

I've never been attracted to anyone before, romantically or sexually, but a part of me wants to be in a relationship, or at least to have someone to be close with and feel comfortable with. However, I think a part of me is also afraid of it, but I'm not sure of what.

I'm not really social, so that may have negatively affected my interest in relationships. But I've met a couple people through online dating sites who have expressed interest in me (we've met several times offline and are on friendly terms), but even something as simple as a kiss or holding hands discomforts me. I don't know why, since both those actions seem very common and not very intimate.

Anyone have any ideas of why a person may be afraid of intimacy? I haven't been abused in the past or anything, nor have I been told not to get into relationships. I never really thought about it until later in high school, and even then it wasn't something I pursued.

I don't truly have any answers about fear of having a romantic relationship. It does open a door to feeling vulnerable.
Are you in scenarios of social involvement, in person, where you are meeting people? Having casual chit chats? Making new acquaintances and potential friendships?
Knowing if you(plural/in general) want something further, also involves a sense of chemistry, which might not be evident, immediately or certainly unknown when just online.
And even if there's a sort of chemistry, in person, there could be other important facts where one needs to use their brain over their heart or chemistry, which takes time in gathering important information about compatibility.

Maybe those met from online lacked key pieces to the intimate equation?

Hmmmm... It's uncomfortable to be intimate, kiss or hold hands with someone you're not attracted to. If you haven't had an intimate relationship before, there's the whole unknown bit and, well, the unknown can be scary just because it's unknown.

I remember someone else who does online dating commenting that they really only "connect,"feel that chemistry with a very small percentage of people they meet irl. Keep meeting new people, you'll click with one, then it'll feel natural to be physically closer.

From the sounds of it, chemistry/ attraction sounds important in order to have a relationships/ be intimate. What if I'm not attracted to anyone? As in, most people I know have had celebrity crushes, or at least had an "I'd tap that" moment for someone, even if they are strangers. I have never had that.

I'm fine with physically holding hands and hugging people if it's friendly, but if the touch entails anything more, it's...uncomfortable. Perhaps it's a fear of vulnerability? I don't know. That might be possible though.

Not ever having had a celebrity crush, doesn't preclude you from ever finding attraction for another, imo. Chemistry can be more than physical, imo. Sometimes it involves mannerisms and intellectual stimulation a sense of emotional bonding, to add spark. Maybe consider the type of person that you'd find attractive, as a whole. Kindness, consideration, compassion, humility are some characteristics that can be alluring.

"part of me is also afraid of it, but I'm not sure of what" "Perhaps it's a fear of vulnerability?"
Could be, as you'd be baring it all literally and/or figuratively. There's risk in that.
Maybe for you, you need a strong emotional connection 1st before you can feel comfortable physically, "safe."

In my case, I'm not scared of intimacy, actually my love for certain people I truly care about is very deep and intense. I'm not afraid of intimacy, I'm afraid that my deep love will scare people and push them far away from me. So to guard my heart and keep others' hearts safe, I create an invisible wall around myself and only people who are patient enough can step into it. This wall create a sense of distance around me.
Nevertheless, if I really can get into a intimate relationship, first I need to feel secure and love myself. Then I want to hold hands, hug and kiss the one I love, or even a gentle touch can make the whole world to stop.