I like them until dating is an option

Howdy. I’m an 18yr old female about to start college and I really like this guy.

He and I have been decent aquatinces/somewhat friends for a little over a year. We only hang out in group settings, etc. Long story short, we recently have started talking more and I’ve begun developing some romantic feelings for him. I’ve been thinking about us dating and feel very excited and happy about those thoughts. He’s sweet and handsome and would be a lovely boyfriend, I believe. Being in a relationship with him sounds wonderful and I want to be in one! However, I’m beginning to sense these feelings are reciprocated and it is for some reason making me lose my attraction to him. This isn’t the first time this has happened to me; A little over a year ago it happened with a different guy who I had a crush on for MONTHS! However, he started to show interest and the thought of dating him made me feel so iffy and I lost feelings tremendously (not completely, though).

It’s not like I don’t want a relationship, I definitely do and I’ve thought long and hard about that fact. I just can’t figure out whats wrong and if someone has any advice it would be greatly appreciated!