I got a job when I was 17 straight out of school with very little experience of under fives. Looking back I would never have employed me!
As it happens I took to it and did allsorts of activities and trips. I went on to college.
If you have a baby I would strongly recomend a quailified experienced nanny. Babies shouldn't be a learning experience in a first job. Make sure you understand what qualification they have as there are allsorts now as well as the newer version of the NNEB.
I would hold a more formal interveiw first where you see there certificates, asks lots of questions about there experience, previous charges and how they would cope in certain situations.
Think up a couple of good ones like- What would you do if you were going into town on the bus and DD no1 vomits on DD no2 and you have 15 mins until you get to the bus stop. Its not about right or wrong answers but how they can think on the spot and how they see themselves dealing with things.
You need to suss out how practical they are, how imaginative, their opinions on disipline and if living-in there habits.
I agree send them on a first aid course, and if lacking in imagination daily suggestions for activities, but you really want someone who understands the benefits of play.
Just watch you don't end up with a babysitter rather than a skilled nanny. The fact that someone has studied child care at college for 2 years shows they have more than a passing interest in children and a bit of staying power.
Skribble SNNEB . (Always wanted to show of my letters).