What's the difference between liking someone and falling in love with someone.

This is what I don't understand at all. My friends tell the differences but I still get confused and I don't understanding the concept between two parties. I never been in love before and I wish I could experience that. If there is signs to tell me that I am in love. I need to know but I really get confused between liking someone and having a crush or loving someone having a crush of vice versa. Especially when it comes to feelings, thoughts and behaviour. I don't really understand the cocept of relationship. When I see people holding hands, kissing lip to lip, being really flirtious etc... I cringe at the sight but somehow I find it cute and romantic. Yes I am a virgin and I never; fell in love with someone, kissed someone, held hands with a boy even sex. I haven't experience that because I am plus I don't know if I am ready or not. Two I am shy person when it comes talking to boys I like or opposite. One time I was disgusted by the sight of kissing and me thinking I have to do that with my boyfriend in public.