Why can't I get a boyfriend?

I’m 21 and I’ve never had a boyfriend, never been on a date, never kissed a guy, never held hands with a guy, never had a guy tell me he likes me, the list goes on.

I’m quirky, intelligent, and sweet. I’m not sure if I’m appealing in the looks department because only girls say I’m pretty. I’m a little on the shy side but I know many shy girls that have had boyfriends and there’s a lot of guys that claim they like shy girls.

I’ve tried striking up conversations with guys myself and they will respond but they don’t seem interested enough to keep the conversation going :(