Sooo many points to hit on. Purdue Vs. ERAU... cost is always a factor, don't kid yourself.
If you are going to double major don't waste your time on aviation. That being said I went to ERAU and I now live by Purdue. Both fine schools, both have great women (ie. Stetson, UF, FSU, and God bless midwestern women at Purdue and in the fine state of Indiana), and both have a lot to do. Neither one will get you to the airlines quicker, that is up to you my friend.
When I was hired at FedEx 4 years ago there were two less than 27 hired right after me. One, I believe, was 24. Don't ever let anyone tell you what you can and can't do. Work hard, be humble, and have fun. Good luck.