Could a girl get pregnant by rubbing naked? Is it easy to get pregnant like that? I didn't penetrate at all or ejaculated near her vagina... Should I worry?

No need to worry, but some serious reading on the process would be advisable.

What do you mean? By reading on the process?

The process of how a female gets impregnated. If you you got precum ON her vaginal opening then the possibility becomes a reality... or either of you got it on your fingers and got it there. You don't have to actually penitrate her for it to be possible to impregnated her... its just numerically more likely if you do.