I wouldn't for a couple more weeks. And even then for very short amount of time say 10-15 mins. I've just gone through something similar and I know it seems to take forever but it's totally worth it
She's a pretty colour Posted via Mobile Device
I'm waiting until spring. I can't wait until I can ride her because she's been a sheriffs horse, you can shoot off her, done rodeos, and ranch work, and does western pleasure with the neck reins and all. Trying to get my gelding to learn that (little booger)
No because with her muscling (or lack thereof) and weight I would worry about causing issues for her (plus bareback its uncomfortable and under saddle you're adding however much extra weight) and because it will burn necessary calories. I would do basic ground work which you can expand as she gains weight, take her for walks. Once she has a little more start lunging (lightly) and once she's good with that start riding (lightly) and then work your way up from there. Would love "after" pics
Looks like she needs a little more weight, but if weight was the only thing, I reckon she looks fine to ride. *However* I think it looks like there's more to it than just lack of 'topline' & (feel like a stuck record...) I'd get a good vet chiro out to her.
Get some weight on her before you start riding her. Have you checked to see if she needs her teeth floated and have you wormed her? If not this would be a good thing to do, it will help her gain the weight. From the looks of her, you are probably going to want to get a cut back built up saddle pad so that you don't sore her withers.
Also you mentioned that you are having trouble getting your gelding to neck rein, try crossing the reins that way when you put the pressure of the left rein on the neck to turn right, it will actually pull his nose to the right. Be sure you are using leg pressure to.