Change of direction at 35?

Hi,

First post for me to this site (not sure it even existed back when I first graduated in 2004).

I've previously graduated in English Lit & law and spent time working in many of the usual areas associated with those subjects (teaching, marketing, law firms, packing in warehouses...).

It's long been a source of regret to me (well, since I turned 30 at least) that I didn't study something more technical at University level and I'm now looking to rectify that. I have my old GCSEs and have also dabbled with some OU study (initial modules in Natural Science) and even completed/survived a Web Development 'bootcamp', so I'm not totally without tech/scientific knowledge. I'm really keen to see how far I can get with a scientific career at this stage in my life.

The options I'm considering (all with the OU as another full time undergrad course is a non-starter at this stage) are Engineering, Computer Science, and Maths/Physics joint honours.

Long term I'm looking to work in either a data role (have dabbled with Python/SQL and a few other bits and pieces) or as a technical writer/project manager (again, with a view to leveraging past experience).

What I'm really looking to find out is:
a) Which of these courses (Engineering/Comp Sci/Maths & Physics) would leave most doors open to me (esp. as I'll be around 40 when I finish);
b) Which of the subjects is likely to prove most challenging/interesting; and
c) Whether anyone has made/is making a success of a similar transition

Cheers