Should I say "I love you"?

I'm 17 and me and my girlfriend have been going out for just about 7 months and I have really strong feelings for her, and she has really strong feelings for me. But I think I love her, but I'm not sure if she quite loves me yet. I'm not too sure what to do about this conundrum. I want to tell her how I feel, but I don't want to push her away, or weird/scare her away, because "I love you" is a scary thing for some people. What should I do?