Don't change jobs or income yet.Once you do and you think you can manage the payments based on your new income, maybe once you get the rooms rented.Then if you want to switch there are plenty of opportunities. 

you may have to save up until you have enough money to do so - down payment, closing costs, reserves, etc.House Hacking: What Is It, How to Start, and Strategies for Successit's a more powerful way to get started. 

Which means that they pay you a down payment and you finance the properties to them.

Do they require payment on site or do they give you a certain number of days to close the transaction?

If you're a single mom with student loans, a car payment, and living paycheck-to-paycheck, then $20,000 would be devastating and a reserve is critical.

The cost associated with insurance for not having 20% is peanuts compared to what you potentially can do leveraging your down payment. 

Your son is responsible for making payments on time or ruining this seller's credit. 

If you decide to keep your house, you can do an IRRRL after you have made at least 7 payments on your new mortgage.

Most mortgage companies will not call loan due if payments are current but you do run that risk and need to be prepared to payoff or refi at a moments notice.

.- get into real estate with a lower rate and lesser percentage down payment.