Concerns About Toddler’s Development.?

I'm a 1st time parent of a daughter who just turned 24 months old. I was layed off work and spent the last year at home with her. I've noticed several things that are begining to alarm me. I started introducing the alphabet (casually) and within 2 weeks she had it memorized by the time she was 18 months. Since then she has learned the primary colors, alphabet, numbers 1-20, shapes,animals in English, (some in Spanish and Sign language) I started word flash cards and she can say and identify over 300 words. So I started writing words on cards and showing them to her and she started reading them. I also purchased a puzzle of the United States and went over the names of each state, etc, and she can say and identify 1/2 the US states. I've only devoted 10 minutes each day introducing her to new things, and from my understanding kids pick up things pretty quickly. I'm just concerned because she is able to recall things so well if it's possible she has a photographic memory?? And if I should address this concern with a Dr or just ignore it and chalk it up to kids just learning things quickly?