Hi Horsef, All!
I'm pretty sure they are born knowing how to jump. I don't know about jumping over poles in an arena, but jumping over logs on the trail is fun. Even George will hop over the occasional log for me. Start small, and wear your safety gear. If you don't already have one, consider getting a vest. I find the foam eventing vests too hot for summer trail riding, but I wear my HitAir inflatable vest all of the time; a wearable airbag!
They are kind of expensive, but all it has to do is save one trip to the ER to more than pay for it's self. As far as I'm concerned, saving me the pain of landing on my 62yo back in the dirt (which it has done a couple of times), makes it my favorite piece of riding apparel :-)
Steve Jernigan KG0MB
University of Colorado