Ditto what has been said above. I did teach myself how to fly, and spent way more time and money than I should have because I didn't know better at the time. Now I do know better, which is one of the reasons I post on this forum, to help people like you. You have been advised, so now it's up to you. If it's just a personal challenge thing, then by all means, challenge yourself. But if you truly want to learn how to do things right, follow the advice given to you by those who have experience.
That being said, I'll throw my 2C on something else. The open field area in your park might be a better choice for a flight area. A baseball diamond might look like a good open place to fly, and in fact, the surface is great for take offs and landings if you can navigate the fences and electric poles. But this is a very big "if". I have a couple of the same plane you have, and it is a very good plane for learning, but it does not like thick grass, and you are asking for failure if you try to make your first flight from inside the diamond. That 4 foot high fence basically takes away about fifty feet of your usable runway, which basically puts you in a "do or die" situation in which if you decide you need to make another approach, you may not be able to the clear the fence again, or most likely, you will force the plane into a stall after you do clear the fence. Just my 2C.