Python is probably an easier language to move onto.
The learning curve of C++ is steeper but you will ultimately learn more (or risk losing interest if you find it too difficult)
I think it depends on how you want to learn and also what you intend to do with programming in future.
I want to pursue a career in it. Coming fall I will be going to college for CS.
Hopefully, at college you will learn a few programming languages any way. If you can find out what you might learn at College, then pick a different one to learn now.
It wouldn't hurt to try both and see what you prefer, there's always value in learning a new language, so there isn't a right or wrong one to choose.
You could also look at Java or C# which are very heavy on OOP which is useful to learn.