Love 💖

I know this is a weird question but I want to know what it's like to be in love with someone. I've been with a guy that I really like and care about a lot for some time now and I'm curious. When can you tell that you love someone? Do you just know or are there like certain criteria that need to be fulfilled? It feels like I might but it could just be infatuation; I'm apparently too young to really know what love is. I don't want to tell him that I love him if it isn't really love and  its just infatuation.