Love, its a strong word right?

after 4 months my girlfriend uses it frequently. She told me for the first time like a week ago. She says it all the time now, I love you...I love you...and shell wait for my response...I do not Love her, yet she uses it so freely so Ill say it back not really meaning it, I just think I may feel that way some time in the future but she says it so freely...it just seems too soon to be saying all that. I do care about her but, she says things like I love you with all my heart, and im in love with you...all the time, this girls trippen haha. I think shes sincere about it, since I never asked how she felt about me and she told me she told her dad shes in love with me, weve had sex a lot, and shes 24...I dunno it kinda just scares me a bit lol