RE:

So I took a day and then I responded to the "grown up" email. I thought my response was mature, well thought out, and helpful for future employment (I sent a few tips). About 2 minutes later I got this response:

I think your right Kylee,

This isn't the job for me,

not even sure why I was refered to you or this job,

by the way, I write well, I hope you don't judge all the candidates by the emails they send you, also, sorry to offend you with the grown up question, I just meant someone who has more expenses that someone your age, because they are older and have more responsabilities, more life experience, more complicated and sophisticated lives, such that they can't live of 1100 dollars a month. I didn't mean to offend you again, sorry.

I probably don't have to point out the mispelled words, the lack of capitalization, and the fact that our dear friend managed to still offend and be rude in his/her apology. Nor do I have to mention that any grown up knows that your emails sent to an employer (seeking a writing, marketing, PR, advertising, etc.) will certainly be judged. What I do want to mention is that I happen to be older than this canidate...which they assume I am younger... and we all know what assuming does!