First most beginner designer seem many website will bad and good designs. Of course everyone has their own opinion and want the good one!

Let said you're between age 15 - 17 starting to design website and you seen the professional design on the web and you say "o, it's pro, I guess it's not my age who made that" and these words come out of your brain or mouth will discourage your design.

The truth is, those pro designers are just like you and around your age. They are not 45 years old etc. They did not take 5-20 years at school or career course to learn this.

So don't give up when you see a pro design, learn from them and make change and improvement for a better design.

That's the heart of a designer.

Inspire the design.

You'll be one pro someday.

Look at bad design to know what's bad and don't do it.

P.S. Average age of 15 starting to be a designer is not a spoil brat! It's their goal, their future.

Good Luck!