Zayzay
First of all can I wish you the very best of luck with your ambitions - I'm sure you'd be a real asset to the RAF. I can answer your questions to the best of my ability - I am ex RAF but have no medical expertise, therefore all I can do is interpret what is on the Student Nurse role page.
a. I'm 30 so not sure if that would go against me,have no kids or commitment.
You must have started recruit training by age 33
b. Are any Religious discrimination as my parents are Muslims but I don't practise, rather nervous about this one with all the bad media at the moment
UK legislation specifically outlaws discrimination for many characteristics including religion - this is NOT, repeat NOT a factor you should worry about. As long as you meet the stated requirements, including nationality and residency criteria, then you're good to apply
c. What is meant by Minimum of 4 years service?does it include the date you started training till the date finish nursing?
The role page specifies that the min 4 years return of service starts AFTER you complete your nursing degree, so you will have to do the 10 weeks RTS, 3 year Uni course and 4 years min
d. Where do they usually deploy you? Does not have to be accurate its just so I know more really and what places. Like for example would you be deployed to active war places etc.
Once you graduate and become an Adult Nurse, then yes, you could be deployed overseas. You would have suitable training to prepare you for this. Locations are likely to be permanent bases such as Cyprus / Falklands or perhaps NATO facilities in Europe. An RAF Nurse friend of mine (Flight Sgt) has spent time in a number of UK bases in Scotland and England, also Germany and at the Camp Bastion hospital in Afghanistan. She did not go outside the wire - bear in mind this was when there was a large UK presence in theatre. I can't currently visualise a situation where there will be a similar UK ground force in any conflict zone - but that doesn't mean there won't be in the future
e. Once you leave is your nursing degree valid to work in hospitals
Yes, you would be fully qualified to work as a Nurse in UK hospitals
f. Finally would it be better to study nursing in local universities rather than going through RAF ?
That is up to you, but not many Uni students get paid to study AND get a salary - the quid pro quo is you'll have a 4 year return of service commitment to the RAF; but if you want to be qualified, do travel and make lifelong friends as well as having sporting and social opportunities that your civvy peers will envy, then, to my mind, it's a no brainer!
Seriously though Zay, there aren't many people here on TSR who can answer all the questions you would rightly have. Why not get yourself down to your nearest AFCO and arrange a visit to an RAF medical facility where you can see Nurses at work, but more importantly, speak to a cross section of both Commissioned and Non-Commissioned staff to get an idea of what the life is really like.
Finally, I can't emphasize enough that your colour, gender, religion or any other protected characteristic is NOT an issue in applying to the RAF. If it was, they would be breaking the law.
Go for it, and best wishes.