First consider how long you've been in the relationship, what the social norm is in your area for length of time and seriousness it takes to get to a "love" stage (perhaps you're just a bit earlier than her, perhaps she takes a little longer), and the point of time between when you started to love her and when you came to feel this way (that your relationship did not have an equal emotional balance).
We all like to see that moment on TV or dream about it for ourselves where we tell our significant other that we love him or her and then they say it right back and everyone is happy; but of course everyone is individual in reality and may develop feelings at different paces.
Really what it comes down to (for me) without any detail or context is the length of time involved here. If you've fallen hard and fast then that's wonderful for you, but doesn't mean the girl/woman is at the same point - but neither does it mean she'll never get there.
If you've been in this relationship for a while and her feelings seem lukewarm rather than loving, first try an honest talk. Very sensitive, non-accusatory, etc. Trust me, women actually love if a guy is willing to show some vulnerability and talk about where a relationship is going - which is a common conversation to have even when feelings are mutual. Where it can go wrong is if one person becomes whiny or cruel simply because the other doesn't feel the same, or if one person is callous about the emotions of the other.
So 1) consider time as an element, 2) have a talk when a good time arises with no distractions, 3) ultimately a split may occur and the acceptance of this is important to your happiness. A breakup can occur simultaneously with feelings of love still in place. The path you want to follow in life, the dynamic you want in your romantic relationship, and your own mental health are more important than holding on to a relationship that doesn't seem likely to change or move forward.
Good luck and I wish you the best for your future romance.