I hope you enjoy using your tablet once you get it!
I started painting digitally about 10 years ago, but I didn't really practice hard until the last 5 years - which is when my skills really started to develop. But how fast your skills get better is very individual, and I've seen artists go from okay to amazing in just 2-3 years. So practice a lot and you'll get there!
They each have their own challenes tbh, it's hard to say which is harder. Whatever you practice the last is gonna be the hardest I'd say xD
Hope that helps!