Feel bad for potentially not taking up role

[SequinsAndGlitter]

I got contacted to help with a 12 year old boy with autism. I have no experience working with children that old although do have SEN experience. Generally I don't feel comfortable with it but feel bad for not taking it up as the nanny job market is so dire right now. Turning down a job in these times feels so wrong.
Am I being stupid to not even try it?

No, if it is not something you have experience with and you don't want to gain experience in that, then perfectly fine to say you can't be of help.

I'm looking for work with babies/toddler and I am not interested in doing before/after school care for school aged children. So if I get a request for care of school aged children, I am turning it down.

If you do not need the money then you can be picky about jobs. Different if you need the money, you may then want to try out what is on offer if it fits around your other commitments. You never know it may be something you enjoy... I have cared for children with autism in the past, one was age 9 and I ended up doing various work with him over the next 10 years.