That depends on what age range you find sexually attractive. Pedophilia refers to attraction to pre-pubescent children strictly (strictly as in the term can't be applied to other attractions, but not strictly as in you can't hold other attractions in addition to pedophilia). Attraction to post-pubescent minors is called ephebophilia or hebephilia. It's quite possible that your 10 year old sister has entered puberty and has developed distinctively female features very early (and of course 12chan serves up ephebophile content). Attraction to pre-pubescent children under 3 (toddlers) is called nepiophilia.

And as I've said before, it's quite possible to be attracted to adults (teleiophilia), post-pubescent children (ephebophilia), and pre-pubescent children (pedophilia), and toddlers (nepiophilia) all at the same time. Furthermore, you can hold any combination of age range related attractions. My personal AoA (age of attraction, a term in the minor-attracted community which refers to the age ranges you're attracted to) starts at about 4 or 5 and goes up to about 65 (it should also be noted that in individual instances you can find attraction outside of your AoA, it's not a strict limit).

The other issue is one of sexual vs. romantic attraction. Many in the pro-pedophile activism community will tell you that pedophilia is a sexual orientation, akin to homosexuality, and not just a sexual attraction. Thus, they contend, pedophilia includes a romantic and sexual attraction. By a strictly clinical definition, used by mental health professionals, this is incorrect. Pedophilia, in terms of psychology, is strictly sexual in itself (this does not preclude the possibility of pedophilia being accompanied by romantic feelings for children though, as is very often the case). You should also consider though that your average person has no idea what "ephebophile" means and often uses pedophile to incorrectly identify them, so you should always take "accepted" definitions of terms with a grain of salt. Some use the term "pedophilia" in a strictly sexual sense and use terms such as "pedosexual" or "GL" (which stands for "girl lover", and is also coupled with "BL" to describe boy lovers) to describe the romantic and emotional side of it. It's all strictly a matter of semantics and petty labeling though, so it's not something that you should overthink.

Generally I've also found that among many pedophiles/sexuals, the romantic/emotional side of their attractions develop after they come to terms with the sexual ones. It should also be noted that pedophile feelings commonly are discovered during puberty for the vast majority of child-attracted adults.

Simply put, the answer is more complex than a "yes" or "no". To fully answer your question, you'd probably need to answer a few more questions:

1. What age ranges are you primarily attracted to, and how attracted are you to them as they compare to the others?
2. Do you feel only sexual attracted to your sister (and other children in general), or do you feel romantically and emotionally attracted to her?
3. Did you find the childish features of your sister specifically attractive, or did you just touch her because she was there and you were horny, as a matter of circumstantial "take it where you can get it" sort of sexuality?
4. Are you largely attracted to younger girls who exhibit adult features they exhibit adult features?

Etc.