I had pretty much exactly the same problem when I was 15. Kept running into books which were either too patronising or too maths-heavy.

To be honest, I never found the perfect book to solve this problem. But, I did find two which I'd recommend:

Introducing Quantum Theory by J. P. McEvoy and Oscar Zarate is an illustrated book. But, don't let that put you off. It's done in a sort of tongue-in-cheek way and it gets quite heavy towards the end. I was really impressed with how much material they managed to get in there. They also spend a little bit of time on the philosophical implications of Quantum Theory, which I've always found fascinating. The best thing about this book is that they clearly tried very hard not to lose you along the way. But, they manage to give you a look and one of the best explanation I've found for the Maths behind Quantum Theory like the Schrodinger equation which, even now, I don't really have the mathematical tools to understand (studying Mathematics at university next year, so hopefully by the end of my degree!).

If you're determined to have a crack at some Maths, I quite liked Quantum Physics: A Beginner's Guide by Alastair I.M. Rae. My favourite thing about this was that you're given the option to do mathematical exercises which will, undoubtedly, further your understand, but you can quite happily read the book without doing a single one and still gain a better understanding of Quantum Physics. Downside to this is that it can be a little dry. At least, I thought so.

Anyway, as z3ro said, there are some great videos on Quantum Mechanics too.