OUCPA: If you have a MAcc already, it'd be sort of bizzare to go for another graduate degree. I'm sure you won't be “blocked” from advancing at your firm – they'll train you on things you need to know.
round1: It's more than possible – but just like for “traditional students” – it is all about your attitude, GPA, social skills, school competitiveness… People in their 30's and late-20's get public accounting jobs all the time. My MAcc class had approximately 30 students – about 15 of us got public accounting jobs (2 of which are in their 30's – and there was only one other “older” student in our cohort). With that said, our program is pretty great. If you get a masters get it from the best program in your state.
Obviously it is a tough job market out there for everybody, so nothing is guaranteed. I'd highly advise against ever bringing up this topic (age discrimination) in front of a firm. If you care, they'll care that you care. If you look like you could pass for 30, i doubt it will have any effect. If you look old, it could make things tougher in an already tough job market, but far from impossible (given that you are only in your 30's so can't look that old).
REG - Passed!!
BEC - Passed
FAR - Passed
AUD - Passed
Study Materials: Becker basic course