Is she in love with me??

Okay so I'm dating this girl right now. We're both 19 and have been dating on and off for almost 4 years. She is the most amazing person I've ever met and I would do anything to make her happy. I love her but am not sure if she feels the same. But I've noticed some signs. She is the always the first person to help me whenever there is something wrong, she talks about our future plans together, she motivates me to be the best that I can be, and she also genuinely cares about my goals and interests. She loves my parents and she always seems to remember the smallest details about me. We can talk for hours and not get bored as well. The problem is that we've never actually had a boyfriend/girlfriend relationship. This is because we couldn't see each other enough due to her hectic life(college and full time job). Plus she has great future plans and doesn't want anything to get in her way. She had almost no social time, but whenever she was free she would spend that time with me. So basically all we've ever done is a casual dating kinda thing. The other problem is that she's the kinda girl that doesn't really show how she's feeling. She always hides it so well. But in the last 4 years we've had our ups and downs. Mistakes were made by both of us that caused us to stop seeing each other. Usually we would we stop dating b/c she would tell me that she couldn't handle not seeing me enough and that it wasn't fair to me. But somehow we always find our way back to each other. This time is different though. We have more time for each other and seem to be closer than ever before. So do you think she is in love with me? And do you I think I should tell her that I love her?