Judy, make sure you read up on fair housing rules, and make sure you identify your criteria for what approves someone to your standards. Do you have an application you have people fill out? This will help you obtain salary information, current and past work information, SS# and information to run credit and criminal background checks and information to verify their employment and past rental history. Kicking someone out isn't neccesarily hard, but is expensive and can be labor intensive. The last thing you want to do is have to kick someone out...
On here you will see a lot of landlords require the persons gross monthly income to be a minimum of 3x the rent. People also have specific credit scores and criminal backgrounds they will accept and reject Etc. Picking the right Tenant is EXTREMELY important. It can make or break you!
It sounds like the "Baby Sitter" has no current job. How can you be certain she can find a job? What will you do if you put her in your rental, she stops paying rent and starts crying to you on the phone saying she has no where else to go with her children on Christmas Day? Just food for thought, renting is a business relationship, not a charity.