Not sure if this really belongs in AIBU, but not sure where to post!
So I live in central London and my friend lives slightly further out of London (roughly 30 minute drive.) She invited me over for lunch today so that our two 6 month olds could play and so that we had eachother as company. I couldn't be bothered with the hassle of public transport so I asked if there was parking. She said, yes loads of free parking down x road and also y road.
Driving to her's was a nightmare and my son cried most of the way so I was desperate to get him out! I found a parking space on the road she lives on and parked up.
4 hours later I return to a parking fine! I was so embarrassed as I had parked almost directly under a sign saying residents only parking. I always check the signage, I have no idea why I didn't check today!! I obviously know I'm 100% at fault and mentioned it casually to my friend later by text in the "look at my stupid 'Mum Brain' moment." My friend is now really upset about it, saying that I'd trusted her and that's why I didn't check the signs. Which is maybe a little true, but I was mainly just being an idiot and don't blame her at all.
Anyway my friend now wants to pay the fine and isn't backing down. I don't know whether I should just let her or not? WIBU to let her pay? I'd feel like I was taking advantage of her good will, but she won't take no for an answer.
(A little bit of background, she and her partner both have good paying jobs and she knows that money is tight for me and I'm not getting maternity pay.)