Does it matter if the guy is younger than the girl In a relationship ?

So i have my ex who is 3 years younger && he says he lOves me but i don't think he knows what love is . After our break up he tried getting at other girls but couldnt . So after.a month he tries talking to me && says he wants to try things all over again so i kind of give him a try but i just doesn't work . So i ask my friend to talk to see what's he thinking && he says that I'm too old bc I'm 18 && it's against the law , but after that he wanted to hangout && wanted to get I'n my pants . But he makes it seem like he loves me but i don't thunk it's true . What should i do oh && he only talks to me when ever he wants .