Graduation dress help - mature with a mum time

[GraduationHelp]

As the title says, I really need some help please, and I'm running out of time.
Mature woman in my 40s, size 10-12, but have a wobbly mum tum. No budget, just not stupid prices.
Graduation robe and cap are black, with red and blue hood.
Thinking knee to mid length. Would prefer to keep to colours above as don't want to clash - but then I have no fashion sense whatsoever, so will appreciate anything people can suggest

https://www.marksandspencer.com/polka-dot-tie-neck-midi-dress/p/clp23042427#intid=pid_pg1pip48g2r2c2%7Cprodflag_Online%20Only

This?

This with a cream silk shirt:

Cos dress

Easy, elegant, both pieces would be versatile additions to your wardrobe afterwards.

Both are lovely, thank you for the suggestions

Do you have an official dress code? Some places do, some don’t.

Congratulations, by the way!

My dd wore this dress from next

I wouldn't describe 40s as mature - what do you mean by that?

I can't help with dress suggestions (I know nothing about fashion), but I'd advise trying to avoid thin and/or silky/smooth fabrics.
I sometimes work on graduations for a company that hires the gowns, and they are quite heavy, with a lot of gathered weight in the back of the shoulders, and on a silky fabric the gown tends to slide backwards and then the front part of the hood pulls right up under your chin. If you plan to pin the gown or hood to the dress to stop this, it can make holes in thin fabrics.
If you're wearing a shirt with buttons, some (not all) of the hoods have a button loop, but if your shirt is worn loose rather than tucked in, it can pull everything up. (Can you tell academic dress was designed for men? )
The hats (mortar boards) fit some head shapes better than others, and will give you 'hat hair'. If your hair is fine or smooth, take hair grips.

Oh, and if your graduation is in a cathedral, assume it will be freezing!

Thank you so much for this info, much appreciated