Overzealous describes someone who gets too excited about something, like your mom, the overzealous collector of cute kitten figurines that now fill every table and shelf in the house.
If you're overzealous about something, you've gone too far, and you're probably starting to scare people. Parents who are overzealous about keeping their kids safe may not allow them out of the house — ever. If you are overzealous about conserving water, you might shower a little too infrequently, or scold people for washing their cars. Most people understand that you mean well, and that's why you are so intense.