Googling will lead you to various roadmaps for learning alg. geom., both on this site and on MO, for grad students but also for undergrads.
One place to start, if you are an undergrad, is Miles Reid's book Undergraduate Algebraic Geometry. Not everyone likes it, but I do, and routinely recommend it to both undergrads and beginning grad students.
(By the way, I work in algebraic geometry, arithmetic geometry, modular forms, elliptic curves, and related topics mentioned in the comments above. I think that viewing things as difficult, or the most difficult, etc., area of math is not very helpful. If you are interested in something, and motivated to learn it, try learning it! Just keep your common sense about you, make sure you do well in your regular classes too, and ideally find a nearby faculty member, grad student, post-doc, or even just more experienced undergrad to act as mentor. Also, although algebraic geometry, once it gets going, relies on other areas of math for background, including various areas of algebra, topology, and geometry, you can try getting into it directly, and then use it as motivation to learn something about those other areas.)