Upper age limit
Regarding the upper age limit - cabin crew over the age of 30 is not entirely unheard of. In my abinitio I had a girl who joined - she was recruited when she was 32. Plus there are a few Pursers and SFP's who I've flown with who are over 40. However, I have yet to see anyone join the company afresh over the age of 35. That's just my observation, I have no idea if the recruiters have an upper age limit or not and what it is.
One exception I guess to this is that if you have a very specific skill that they may see will become in handy, such as nursing experience. From this they may see you on line for a few years, and to then tranfer over to the training college to train abinitio crew. I know of one person who went from Economy crew to service trainer having been with the company for only a year and one month.
To be honest though, none of us have any idea whatsoever as to what the recruiters may be thinking and who will be the right 'fit' as an Emirates girl or guy. Personally I would just go to the open day, because you never know beforehand if you have a chance at getting picked. It is truly a dream job and I encourage anyone, regardless of age, to have a go.