Potential rental applicant raise my set rent

[Crystal Shi]

Hello experts and fellow friends 

I have a property just became vacant. I marketed $3000 rent/month which is the average rent in the area. It attracted a lot interest but most of them don’t quality for it. My set standard is $9000 income with over 650  or better score. No aggressive dog and smaller dog preferred. 
Yesterday I received an application from a couple with $8500 and above income (the husband is $40/hr and depend on the working volume the income is varying). They have one small dog. Everything checked out and I would like to go with them.
But the other applicant approached me(she came right after the first one yesterday) and mentioned she wanted to raise the rent to $3250 and offer extra deposit. She and her boyfriend combined income is $16000 a month and their information also checked out. They have two large dogs. Both men in the household have superior credit score. Both women have above 600 score. 

The extra rent seem tempting. but I already told the first tenant I would like to accept their application. I’m not sure if it is the right thing to do to move on to the second applicant. She seems to love the house and very motivated.