My sister thinks my boyfriend is a bad boyfriend?

I have been dating my boyfriend for almost two years. I'm 16, and he's 17, but turning 18 in a month. He's going to college next year, but i'll still be a junior. We've both dated other people, and we really love each other. We've talked about it, and at the risk of sounding naive, we want to be together for the rest of our lives. But my sister thinks he is a bad boyfriend. I can see where she's coming from, because all she sees are the flaws in him. Sometimes he can't come hang out with me until 8 or 8:30, and to my sister, a 13 year old, that seems really late. Sometimes he says we can hang out, but then is too busy (he works and on top of that has other things to do, so i understand, he's just busy). And all we ever really do is hang out at each others houses, pop in a movie, and cuddle. And that is perfectly ok with me, i even prefer that to doing something else. But my sister thinks its lazy and not putting any effort into our relationship. But she doesn't see the sweet, caring, genuinely good hearted man that i do. He's dorky and sweet and nicer to me than anyone has ever been. I have countless examples of how he is a wonderful boyfriend, and a much better person than anyone else i have ever dated or met. Why can't my sister see that he is good for me?