I think it's a bit odd that your mum had an expectation that she would be there? Don't take this the wrong way, but surely she should be taking your lead on things and supporting your decisions?
I have to chuckle at your blissful naivete! I know mothers who are very un-presumptuous, and I also know of mothers who take offence at being excluded. My own mother did not only take offence, she didn't talk to me for 10 days afterwards (and wouldn't 'give me the satisfaction' of validating my choice by even seeing her grandson in person) because she thought she had some 'right' (that she never discussed with me, incidentally, until after the fact) to be involved...and when pushed about this, couldn't and wouldn't pinpoint just at which stage she thought she should be involved. She had her own adjustments to make and thought that being there would have made all the difference. If we had another kind of relationship, perhaps. Had she even discussed it with me, perhaps. She knew I just wanted DP and I there and she never contested my wishes...just silently seethed about it. Most constructive
Anyway, it boils down to YOU being comfortable with the people there - no better way to slow down labour than to be unsure of whoever's around you. We're mammals and our mammalian brain takes over during labour and birth, seeking security and comfort to birth optimally.
If YOU are comfortable with who's there, that's all that matters, cos chick, this time it is ALL ABOUT YOU. And the 'you' incorporates your child - you are inseparable entities at this time and post-birth. If you want your mother there and your DP doesn't, then the fairest thing is for him to deal with his issues and let that happen. If you don't want her there, then leave instructions with the hospy staff - they'll comply
This time I'm going the homebirth route and thought about involving my mum with DS for a little while. She started quoting AMA and RANZCOG comments from newspapers to me so she was left well off the attendee list! There is no way she's going to be there whilst she's so ready to criticise the way I'm going to give birth. The first time round she kept saying 'I am praying that you don't have too much pain for too long', and when I told her I'd be fine because I'd done my HypnoBirthing and it was likely to be a great birth she said I needed to 'trust in God' instead. I wasn't going to have her vocalising this to me during labour, making it all about her and her wish for my 'salvation', rather than respecting my birth plan. That was a FBC birth, so I don't trust her enough for my current plans! Her reasons for wanting to be there were about HER and she still rejects that DS's birth was when it was allowed to be about ME.
Not one single person has an automatic right to be there at the birth, not even the father. Everyone needs to realise it's a privilege and that there are strings attached!