See, this is what I was slightly ranting about before. In the topic I posted about critiquing the Rhinelander Gelding I'm interested in getting, you said that it's not about the horse's conformation or over all looks...it's about the bond...
You seem to be contradicting yourself quite a bit. You speak like you understand your mare and you would do anything for her. If you really cared for her you would realize that she physically cannot put up with jumping nor should be be barrel racing. I mean, not only does she have poor confirmation, she's also getting older, is blind, and cannot bend or flex her leg due to her missing a tendon. I'm sorry, I have to ask - what the hell are you thinking? It's time you give that mare some respect back and retire her. She served you long enough and pushed her limits for you. It's just a matter of time before something happens to her, you, or both... you can semi-retire her now, keep her as a pleasure horse with light riding but no...just because your mare keeps giving, you keep taking.
Your parents seem to be the type of "horse people that I cannot stand" - I would have expected older/wiser minds to tell you that your mare can't take it, but you're just a family of "horse pushers."
Your dad seems like an complete jerk. I have showed an Oldenburg  in level 6 jumpers, he also did the Grand Prix level... that horse was smart, talented, and very athletic. Not only was he the best competition horse I have ever shown, he was my friend. If I didn't trust him on a "friend" level, I would not be jumping him that high and across those spreads.  He was also VERY expensive, and it would be horrible to push him that far to the point of breaking him (not that I would be so cruel to do that anyways).
Equestrian sports are all about team work. If a horse trusts you enough to let you sit on their back and preform with you, you better be respecting them back. You speak about a bond... if you had a bond with your horse, you would understand her...you would know her limitations... Seriously, if your not in tune with your horse, you shouldn't be riding her anyways, let alone competing her.
If you really love and care about your horse, you'd  grow some balls and stand up to your parents and tell them that horse has slaved for you and your family long enough. Any real horse person would see that.
Also, if your vet OK's you to jump and race your horse, he/she is truly an idiot as well.
As for working with a baby, I honestly think you wouldn't know what's best for it and will probably push it so far you'll ruin it...
(I'm sorry I have to be so blunt...)