Is this normal or should I be concerned? I just took her to the bathroom before she came on and she peed.
Looking back I think Cassie was about this age when she regressed for a while. It turned out something had frightened her in the garden and she didn't want to linger out there! I didn't know what had happened for a while and just had to go back to basics. It might also be worth checking out urine infection.
Accidents are common during the first year. And with a female dog (unless she has been spayed) accidents are also common around the time of the first season. But if it happens again without any obvious cause, then a vet check is a sensible next step