AIBU to not split the bill?

[NYC23]

I went out for lunch with some friends, 6 of us, to a nice place in Chelsea, and we ordered off the menu (not a set menu).
The other girls had starters and I did not. I was also driving so drank only tap water. 4 of the girls had cocktails, at £14 a glass and wine or prosecco...
I only had my main and then obviously would pay some money for a tip.
The bill came and someone said "shall we split it 6 ways - it's easier" I had a quick look at the bill and mine came to £18, and everyone else's was over £50...
I said that in different circumstances I would usually be happy to split if we had all had a similar amount but I wasn't happy to split it on this occasion...
I felt like I was being judged and one of them was really snappy with me about it.
AIBU to not just agree to split the bill? I thought I was ok to say no but now I'm second guessing myself :/

Have been in a similar situation on a hen do n really annoyed the hen. I was heavily pregnant and suffering so just had a main n tap water. Glad I stuck to my guns, despite being tutted at and having the bill snatched back. Yanbu at all.

I'm generally a bill splitter. I tend to be a relatively small eater and don't really drink so it's certainly not a case of wanting my meal subsidised. It's just the way it's always been done in my family and friendship groups. If it's just a couple of friends we sometimes do a "this ones one me, you get the next " kind of thing.

But with a large disparity like this there is no way I would expect the OP to split! I would have taken the cost of her main off the bill and split the rest.

YANBU. It's only ok to split the bill equally if everyone has had more or less the same amount.

In your case I think it would have been fine to put in £20 or £25 and say that should cover the meal and the tip.

If we have been out for a meal and there are non-drinkers we would normally split the food equally, then split the drinks bill between the drinkers, although I would be mindful if someone has only had 1 drink and everyone else has had loads. I would also never order £54 lobster in a group setting if everyone else is having £18 pasta dishes unless I was prepared to stump up extra for it.

Your 'friend' doesn't sound very nice.