Advice for acceptance and holding fee- newbie question

[Matthew King]

I'm brand new to REI and being a landlord. This is my first time posting although I've been watching and listening to the podcasts for several months. I've been talking to friends in the business and reading a lot (most recently The book on Managing Rental Properties). I just closed on a townhome in my area about a week ago but advertised the home about 2.5 weeks ago. I'm currently renting back to the previous owners till the 24th. I've shown the home to 1 family and have 2 more interested people scheduled later this week. I've screened many through text and phone and honestly only 10% seem to qualify for a showing which I've gathered is fairly normal. The family I just showed it to is a single mother with 3 kids. Seems to have a stable life and down to earth. I ran a credit and background check and got pay stubs. Here income is 2.8 times the rent price and her credit score is a high 814. She does have some car and student loans totaling 54k. I will call her employer to verify income employment. I know the income is just shy of 3 but it's very close and her credit and loan history are near perfect so I'm thinking it's a go from that perspective. Do others agree?

The unit is available on the 25th and she wants to move in on Dec 1st.  She wants the unit.  I'd like to move forward with signing a lease and take it off the market in the coming days.  I'm thinking of asking for the security deposit of first month's rent ($1790) and an additional $500 holding fee that will be applied to the first month's rent on Dec 1st.  Does all this seem logical/reasonable?  I'm very open to other thoughts and recommendations.