How To Pick A Sweet Kitten?

I have a 4 month old kitten that I want to adopt. She is very sweet and playful, but there are some things about her I don’t like. My previous cat was much larger than my new one, so she’s kind of shy in the beginning when meeting new people or other animals. Also she scratches sometimes when playing with other cats since she doesn’t know how they act around their nails (she’s only had kittens at home). Do you think it would be better if I get another kitten? What kind of kitten should I get? Oh yeah, what were you doing all this time without me???