Questions about my girl going into heat

Hi all! My girl honey is just about to be 9 months. I had planned on having her fixed and called her vet last week and they stated I would need to wait for her to go through her first heat cycle and then once she does to let them know and they will get her scheduled. She ended up going into heat this week. I’ve never had a female dog so I’m just trying to understand if I can make her comfortable and if her behavior is normal. She’s mostly herself but just extremely whiny and clingy and doesn’t want to play normally when we go outside so we’ve been taking it easy. She also seems kind of on edge. Is it normal for the vet to have you wait until after their first cycle? Just looking for advice! Thank you!