I totally understand how confusing these things can be when you are anxious. Yes, it's possible even without full penetration if fluids get close to the opening. Take care of yourself, dear.
A helper sperm doesn't need an invitation or full penetration to find its way! If semen is anywhere near the entrance, pregnancy can happen. Trust me, biology is wild!
Actually, no, even pre-ejaculation or semen near the area can cause pregnancy without deep penetration. I had a lot of complications during my pregnancy, so I highly recommend talking to a doctor if you are anxious about a missed period.
Even without full penetration, if semen gets near the vaginal opening, sperm can swim up and cause pregnancy. I kept up with my light prenatal yoga and walking only because my doctor said my pregnancy was perfectly safe, so keep these things in mind.
Listen dear, full penetration is not always necessary; if there is any semen near the vagina, there is still a small chance of getting pregnant. Don't stress, but be cautious and use protection to be safe.