You brought up a couple of different questions. Age has no bounds. One can fall in love with anyone — older or younger.
The key in your description, however, is how you talked about fantasizing. That makes me wonder how much in love you really are. This is something you need to consider. If you are focusing on fantasy and not looking forward to real-life events and relationship growth with another person, then you might end up very disappointed.
That’s not to say that it can’t happen. Of course it’s a wish come true that our fantasies come to life. If the two of you are in a real emotional relationship then you might share your mutual fantasies with one another. That could actually add to the enjoyment of the partnership. But if you have secret fantasies that you are hoping for, and not making it a common desire, then it probably will never happen.