I've been getting pictures all year of a fawn born this spring. It actually still had it's spots up until the last couple weeks.
I can't see any bumps on its head where antlers might grow from next year, so I'm assuming that it's a doe.

I'm wondering how old this doe will be before it can be bred by a buck. I'm guessing next years rut? I know at 1 1/2 years old it will still be small, but getting pretty close to a mature doe size.

Anyone know if the bucks tend to leave doe alone during the rut until they reach a certain age/maturity?

In many parts of the country, body weights, not age determine when a doe is sexually mature. In northern states and Canada a doe fawn can be bred if she reaches a body weight of about 80lbs.

Yea health of the deer has as much to do with it as age. A healthy doe fawn will generally be bred as soon as she reaches 7 months old, assuming she is healthy. In Wisconsin, the does don't always hit the 7 month milestone until after the rut hits in mid-November, but they will go in estrus during December or even January and will most likely be bred as long as she is healthy. I'm not familiar with when fawns are generally born or when the rut is in Texas, but if she's big and healthy and old enough, assuming the buck:doe ratio isn't too out of whack, I'd say she'll probably get bred this year yet. On a side note, bucks can successfully breed at 5 months, as long as they are healthy and somehow find a receptive doe that isn't being trailed by half a dozen racked bucks.

Ya that 1st year I thought they could be bread....which often times is during the 2nd rut....

Seems like the bucks around here prefer the younger does. I really suck at aging a doe but I would guess that the majority of does on my hunting grounds are probably under 2 years old. I have a doe on my stuff that was a young fawn last year that was attacked by a dog in front of me leaving a significant scar this year. She now has two fawns of her own and she cant be over a year and a half.