Now why didn't anyone think of giving ME a lathe when I was 13? Soooo jealous.
Good work with the bowls, Dan, I like the Iroko one best, it's interesting how you got the square shape on the inside. You seem to have achieved a better finish on the iroko too, though I don't know how, that stuff must be lethal on tools.
On the ash ones you can see tool marks which is what we all try to get rid of. When you're a beginner like you and I, you don't have the skill to sharpen and use the tools really well, and so you have to resort to sandpaper, and lots of it. Stop the lathe every now and again to inspect the work for circles, and be prepared to sand with the lathe stopped, always in the direction of the grain, to get rid of a certain blemish before continuing down to the next grade of paper ( I think I can see a box of sandpaper strips there in the photo, they'd be 150 -400 grit) And be careful of the dust, do you have some sort of extraction? Remember, sanding dust is really BAD for you. At least wear a mask.
You seem to be attempting a wide range of projects, which is great, it makes you think and that makes you improve without even realising it. Keep those bowls and compare them with what you make at the end of next year, you'll see such a difference!
Have you considered entering the challenge? I don't know if you'd be the youngest member to have entered, maybe someone could advise on that one?