"Overzealous" means being excessively enthusiastic, passionate, or intense about something to the point where it may become overwhelming or extreme. Full definition
Foreign oil companies would refuse to dish out any more money to develop the country's resources if it knew that it could be kicked out at any moment by overzealous prosecutors in small towns. (fortune.com)
One boy got a little overzealous in his play and pushed a girl, knocking her to the ground. (relevantmagazine.com)
Amandla Stenberg: The young actress continues to experiment with her style, and here some might say that it looks as if she got a bit overzealous with the splatter paint in this creative, throwback twist on the Canadian tuxedo. (redcarpet-fashionawards.com)