Hopefully my contract will be accepted tomorrow for the property, there is a good chance of it, and its our first one so pretty excited and nervous. 

Ive worked 3 years to get to where I am but i dont know if I should give up the chance to get this cred.All info would be helpful!

The reality is that only 10% of tenants are actually bad so your odds of getting another good tenant is high, Chances of a bad one before screening is 10%, after proper screening probably 1% or less.$300 dollars may not seem like much but business does not operate based in building in unnecessary on going losses.

My hopes is that someone will take a chance in me

And yes to @Jailen Holt's question: Do you have any referrals by any chance?

Chances are she will also be leaving as well in a few months or worse case be evicted and at that time you determine how much of the DP is returned to her.  

We wanted to help out a neighbor and give him a chance to earn some side income on this flip.

It is very simple for me to say do this do that and I do not sugar coat that advice but you must be aware that implementation requires experience and skills that not every landlord has...For example when I advise evicting and the response is the cost is too high/give the tenant a chance that indicates a landlord without the experience to see long term. 

But she knew the previous owner was an ***hole just like I knew he was and therefore knew there was a better chance he would be lying rather than me.

Chances are they will both leave.