Is late puberty mean I did a bad thing?

Highly doubt it. A little more information would help: girls or boys (they're different?) what age? What pubertal changes have happened, if any? Chance that it's anything you or anyone else 'caused' is unlikely.
Puberty. Not usually. Late puberty is usually beyond anyone's control. The one major exception is if you have an eating disorder or are extremely thin. The body needs a certain amount of lean mass to go into puberty.