Awkward shopping experience

My son called a trans woman a he today it was so weird there was awkward silence afterwards, and I remembered my dorm years when I called a flatmate who was trans man a she and I was cut off from the whole group and spent the rest of the university years by myself, my son is three so I couldn't correct him I just kept changing the subject while he kept saying he in the shop, she was wearing makeup and had a dress but had a small mustache with a manly voice and what clearly is a wig, I had to leave it he shop because after what happened in my dorm I would never make that mistake again.