But what right has your mother got to impose rules on your life.....none, me I'd have gone to see a solicitor to find out just what the legal position would actually be.
You are a consenting adult, and are free now to live your life the way you see fit, of course, where family is concerned there are sensitivities to take into account, but, well I don't know what the rules are where you live, but here in the UK, you'd have to be in feminine mode 24/7 in order to get transition, and as that comes in the Harry Benjamin Criteria too, under which most TS's are treated.
You talk about not being en femme, as it were, at work, but what you say implies that you, and your mother work at the same place, rather than you working for your mother, I'm not sure which way round you mean, but if it's the former, she cannot impose rules on you, at work, specially if they conflict with company policy!