I think your base is good enough with any part-time program. You have high GMAT, and decent GPA. 3.1 is not that bad. Honestly, I don't think MBA schools care that much about undergrad rankings.
Your age of 25 is also appropriate, because I don't think MBA programs want older guys that much. EMBA is a different story, but for Part-timers, 25 is perfectly fine, if not an advantage.
Now that you have your base covered, you have to work on other parts of your application. This is key. At your current work experience, did you get promoted? Do your recommenders love you? Do you have concrete career goals, which you have already put into motion (have examples to show you have been working towards those goals already)? If your answer to the above are Yes, then you should most definitely apply, and I am willing to bet that you will get into any part-time programs.
If the answer is no, I think you should still apply for the experience. It can only help you. Now, if you don't get in, you know what you need to work on. Create a vision of your career, start taking actions, get promoted, or show clear signs of your career progression, and reapply. It could take 1, 2, 3 years, but now you are still younger than 28, and it's ripe age for an MBA.
Hope that helps.