I can't tell you which place to work at. But, the best advice I can give you which will carry you through the rest of your life is....
Apply to the new job, Interview, Listen to the offer for hire, If you are interested in the new job then take it starting ASAP, then take a week off at Petco (Tell them a family member died and you need to travel to another state with your parents for 4 days) work the first few days at the new job and if you feel you do in fact like it then go ahead and call your petco boss and quit. If you don't like the new job then you can always go back to petco and they will have no clue.
Now the only bad part is the lack of 2 weeks notice (Which should be given in a "career" type position) but cmon it's petco. It's not like you will be black listed in the industry if you don't give them 2 weeks notice.
Bottom line is always have a new job to go to before quitting the old one.
Apply to the new job, Interview, Listen to the offer for hire, If you are interested in the new job then take it starting ASAP, then take a week off at Petco (Tell them a family member died and you need to travel to another state with your parents for 4 days) work the first few days at the new job and if you feel you do in fact like it then go ahead and call your petco boss and quit. If you don't like the new job then you can always go back to petco and they will have no clue.
Now the only bad part is the lack of 2 weeks notice (Which should be given in a "career" type position) but cmon it's petco. It's not like you will be black listed in the industry if you don't give them 2 weeks notice.
Bottom line is always have a new job to go to before quitting the old one.