I can't see the pistols in the photo but it certainly sounds like a female. If you have height issues it's best to bend or tie limbs that get too close to the lamp. Since you're growing from seed don't be surprised at how fast they'll stretch. Sometimes they can triple in height the first 10 days of flowering.

Just don't panic yet. Once you pull your males you'll feel better and have more room.(Though height won'tchange)