I can't shake off this notion that she may be into me.
Probably more than just a 'notion' if she's:
touch me a lot on my hands, shoulders and back
rarely take her eyes off me
If she touches you, it's because she "means business".
Basically either do it or don't do it. If you do, there are all the usual problems and you'll probably regret it. If you don't, you'll definitely regret it but won't have the problems. Only you know the answer and if you don't you're probably daft enough to do it anyway and sod the consequences.
I'm a very attractive young guy
If that's true, you should be getting plenty anyway without getting involved with a married cougar who touches you up - they are ten a penny and this one sounds like trouble. If you live in a big city, why not - you can just walk away from it and block her calls. make sure you don't ditch her just after sex and get nice texts/emails in case she cries rape after you've dumped her.
If you live in a smaller place and you're both in the same community, better not even go there.
Too late to edit the last post but just a bit of advice. Older people (regardless of the genders involved) who flirt gently and nicely with
very attractive young
people are often thoroughly decent. Older people who
touch me a lot
are usually bad news. Stay away unless you want more hassle than sex.