It's best to wait until they are at least a year old before breeding... it helps the momma reach her full potential without having to provide nutrients to growing babies. Also, cuts back on birthing issues. :)
I had one of my bucks escape his pen and breed my not quite 5 month old doeling that was in heat. She was 10 months old almost to the day when she gave birth to healthy twin boys.... she was a great mom, produced plenty of milk for them and now that they are weaned I keep catching her nursing...
Sounds like she was in heat.... I guess you'll know for sure in another 17-21 days! LOL I had 3 doelings this year come into season at 7 weeks old, 10 weeks old and 11 weeks old :barnie..... luckily they were all quiet though!;)