Congratulations on taking the step to wear hijab, some of us on here do, and some of us don't, and some of us are considering it, so you will find support and understanding here Inshallah.
I'm not learned in these things, but I have to say, well done you for trying to maintain your family ties, it is an Islamic value we are all commanded to maintain our family ties and to treat our parents with love and respect, regardless of their religion.
I've never been in your position so I probably won't be much help with the advice on how to get your family to accept your decision to wear hijab.
I have however experience of difficult mothers! This time last year was very tough for me subhanallah, as it was my first ramadan after my divorce, and my mother was clearly having a hard time coming to terms with my newly acquired status, so she was I felt pushing me and pushing me. I think she felt responsible in some way as she had arranged my marriage.
I work so I had to rely on my parents for help with child care that year. That ramadan, gosh did I make heartfelt dua, that my mum stop hating me so much that Allah help me and give me support and strength, and gosh I must have wept several oceans of tears... However it is my very own resolve never ever to speak out of turn to my mother, or my father for that matter, and I never said anything to my mother, if she ever brings up my divorce I tell her it was Allahs will, it was wrtitten and never meant to pass me by, and I accept what Allah has written for me gladly, I don't mind all, there is lesson somewhere in all of this and possibly this affliction has deflected some greater one that could have broken me completely...
The point of my waffling? Well before Ramadan ended, I had acquired a wonderful muslim childminder, and this year subhanallah, my mother insisted I come to her during ramadan, and she has been so loving I sometimes want to look over my shoulder just to check she's not talking to someone behind me....
My point I guess is that make dua for your parents, make dua for yourself, inshallah this too shall pass, and because you have taken the hijab for the love of Allah, Allah will take protect you inshallah.
Also if your mum is antagonistic about Islam, just dont talk about it, if she asks you something answer but no need to make every conversation about your religion, and if she says something calculated to upset you, take whatever she says literally, I do the wide eyed innocent reply to rude questions all the time, generally the questioner does not have the gall to repeat their question or remark in more detail!
If you need IM me, I'm in London too.
I'm sure you will get a lot of responses inshallah on here. And welcome to the board.
Lots of love and duas