I was more or less at your stage a few months ago and I appreciate what it's like seeing some of the frankly great shots of little ones on here then having your first go and being a bit disappointed that your results are nothing like it. The previous poster's comment about guitars is a good one. I got a guitar at 16, plugged it in to the little 5w amp that came with it and simply couldn't believe I couldn't get it to sound like Jimmy Page and Ritchie Blackmore.
I feel I've improved a lot through reading this forum, watching youtube vids and learning to understand how my camera works, how one setting affects others etc. It's a steep learning curve at first but does pay dividends. I did my first shoot for someone else a couple of weeks ago and still look at the results and can't quite believe it was me who took them, but the results were the result of a lot of advice and information and examples from people on here who take the time to explain, patiently, often for the thousandth time,to noobs like us.
My comments on the above pic. The lighting is a little better but it looks a little underexposed to me. The focus also looks a little soft, possibly because you've used a wide aperture giving a very shallow DOF. I struggled with this myself when I did my first shots with my daughter. You use a wide aperture to let plenty of light in as you don't have a lot but end up getting a soft focus.And as kids simply can't keep still, you end up with them moving out of the shallow DOF. The second button on his outfit seems to be the sharpest point. In this composition, your background is not apart from the subject so it's not like you need to achieve bokeh on it so you could close the aperture up so that everything is sharper. You wouldn't want to make the exposure too long though as kids move all the time so you'd either need to up the ISO a bit or, preferably, increase the lighting strength. I'd also go for a less bright background that will make Junior more the focus of the composition.
To get more comfortable with settings, take lots of shots, with different settings, and get a feel for how this affects the result, and what you also have to change with other settings. It's one thing to read the advice but to take half a dozen shots of something, changing aperture, then some changing ISO, then some changing exposure, ten changing lighting settings etc and looking at the results can teach you so much.
You've already got the most important components, enthusiasm and a want to learn. Everything else is just learning along the way, and a lot of trial and a lot of error but you 'will' quickly reach a point where you take some shots and go Wow. Did I really take this photo?
The knowledgeable peeps on this forum will get you there. Keep it up mate. I look forward to seeing more from you.