Join Date: May 2012
Location: Chicagoland area, IL
I agree that you really need to have a jumping instructor come and help you out at least once... just so you have SOME sort of direction. Also, I personally would invest in a jumping saddle... it doesn't have to be expensive, so long as it fits your horse properly. If you're unsure how to fit a jumping saddle, ask the instructor for in assistance in that as well. Jumping in a western saddle is -- as others have already mentioned -- hard on the horse's back, even if it is light, and you WILL run the risk of breaking ribs.
Personally, I would NEVER jump a 4 year old more than once a week, even if it is over low obstacles. Horse's bones aren't done maturing until they are around 5 or 6 years, and at the age of four they are, believe it or not, STILL getting used to their body and growing legs. Babies tend to be clumsy, and -- let's face it -- if you don't know how to properly set up the horse for taking off, going over, and landing off a fence... it could be very easy for a young clumsy horse to land wrong and injure the immature bones & ligaments. Obviously, low fences shouldn't pose such a threat, but until you know how to hold a horse up, two-point CORRECTLY over the top, and balance them evenly in the landing, I'd stay away from those three feet logs for a year or two.
Jumping appears to be so easy, and for some horse & rider partners, IS. But it is also VERY dangerous, and one bad jumping experience could scar you & your horse forever... both physically or mentally.
Be safe, have fun, and good luck! :)