To be pregnant, 2 criteria should be fulfilled:
1. Fusion of sperm with ovum to form a fertilized ovum.
of the fertilized ovum in the Uterus
So, the involvement of sperm is needed.
If you have pulled out before ejaculation, & sperm has not entered inside her genital tract, then there is no chance of pregnancy
However, the pre cum (pre ejaculatory fluid) also has low levels of sperm.
So, even if this pre ejaculatory fluid (pre cum) enters into the genital tract, the sperms present in it can fertilize the ovum.
Hence, resulting in pregnancy.
There is no need to worry, you can wait till she gets her periods.
If they are delayed, a Pregnancy test can be done to confirm it.
In case of pregnancy, it will give a positive result within one week.
Wishing a Good Health.
Let me know if I need to clarify further.
Thanks & take care.