That doesn't seem to be a very large space to practice in. If you're in trees, get up high above them. "Drone Awareness" (control according to the drone position, not your relative position to it) is always most important. I found it best to practice a lot in "Angle" mode. starting out in anything else, confuses you once you switch to pilot.
I took my Grand-daughter out Saturday, she's 10, and under strong objection of my wife not wanting to see our investment (I use it for my business, inspections) crash and burn, I did it anyway. Started out so basic as spending 30 minutes with her on instructions of how to use the sticks, FAA rules along with basic safety rules, what to expect out of the UAS, and how it would respond. I did a quick 5 minute demo for her, and then landed. To her credit, she paid attention to every word I said. I started her in turtle mode, and in "Angle" mode, and with the drone facing away from her, so the controls were relative. She took off on her own, and I instructed her on the function of the sticks with her controlling them (forward, right, left, back, yaw left, yaw right). Then the most important thing to learn early on - "DRONE AWARENESS". I had her get high enough (30 ft. or so), and then yaw all the way around, facing us. She understood then, that forward stick was back, right was left, and so on. When the battery died, she landed, and learned how to turn the video off, drone off, and change the battery. She took off again, and I put her in full rabbit mode, and she flew that bird like a pro through two more batteries, on up to 203 ft. above ground level, panned the entire area, etc. before her fingers got so cold she wanted to stop. Of course, being the proud grandpa, everyone that I e-mailed after that got the subject line "If a 10 year old can do it.....". It was a most perfect day.
Oh yea, when we got home, she told my wife "Grandma, I've got good news, and I've got bad news - the good news is, I got 5 ft. in the air with grandpa's drone; the bad news is, grandpa needs a new drone". After my wife's terrified expression, my grand-daughter couldn't keep from laughing. I think I'll have to take her out on my inspections as my PIC (Pilot In Control).