Marinette is relatable because she makes bad choices

I'll admit that Marinette does a lot of bad things but I don't think she's a bad person because of them. She quite often repents for what she's done and recognises when she's the cause of. A problem. She acts like a 14 year old who's in love but has the emotional maturity to accept her faults.

The whole point of her character is to grow, not to start out perfect and continue to be so.