I want to tell you something about myself: I had sex with a girl. She is 12 years old and I am 15. I don't know about her period or whether they happen or not. After sex, I did not get my sperm in her vagina. All sperm was cleaned frin my hand with a cloth. But maybe my hand wasn't completely clean and my girlfriend pushed her vagina against my fingers. I think a little sperm might have adhered to my fingers. My question is: Can she get pregnant?
What you did was very wrong for many reasons. As an older boy, you took advantage of a younger girl for your own pleasure. It doesn't matter if she agreed to it or not. It is also wrong because it is a sin before God to have sex with someone you are not married to. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4).
I assume you mean that you did not ejaculate in the girl, but you did have your penis in her. The problem is that before you ejaculate, you drip pre-ejaculate fluid -- that clear fluid that drips from your penis when you are sexually aroused. That fluid can contain sperm.
Wiping your hands for semen reduces the quantity of sperm present, but does not eliminate the sperm. Since you touched her vagina, there is a chance of transferring sperm.
The basic rule is that anytime you have sex, there is a chance that you can get a girl pregnant. There are various precautions people take, but all they do is reduce the odds of pregnancy. They do not eliminate the possibility.
You will know if she is pregnant or not after she is supposed to have her next period. If she has a period, then she is not pregnant. If she doesn't have her period, then she is either pregnant or because she is young, her period was skipped. Only a pregnancy test at that point can tell the difference.
But regardless, the two of you sinned and that need to be corrected with God.