J.E.
Well..I dont know if its "normal", but if it makes you feel any better, my 4.5 yr old is the exact same way. She has been counting, knew shapes/colors/alphabet, etc since she was about 2. She talks great...knows words and what they mean sometimes that I didnt even know she knew! But..she has a hard time with letters and what their sounds are. She knows her name, how its spelled and can write it perfect...but when it comes to letters besides her name she struggles. I think its pretty common. Just work on it with her. We picked up a couple preK workbooks from walmart that give her some extra practice each night. She loves it. Have fun with it!
Good Luck :)