Dear Paolo,
I think you have started to answer your own question. This answer lies in your career development. The first step to take is to identify the new direction you wish to take. You should then build a few profiles of the types of jobs on offer down this new direction and identify the characteristics of the people in these jobs. Once you have build this profile in terms of education, experience, and so on. You then need to match to your own experience and qualifications. This matching process will help you identify the types of jobs you could get, the experience you need for other jobs and the education you may need to acquire. You can now determine how feasible your new path is and the course of action you need to take. If the route is not clear then I would try and speak with people in the role you are looking for to determine how they got there.
So you need to undertake research and some networking.
If the question simply comes down to education then you need to undertake the qualification that is best suited from your matching process. If there is a qualification the industry expects you to have - lets say a hygiene factor - then you need to acquire this. If you don't have it you won't get through the first phase of some job screening processes as this may be done by agencies.
In the debate about MBA versus MSc then both qualifications should give you subject knowledge. The MBA will be more focused on strategy, decision-making and leadership (assuming it is AMBA accredited) so will appeal to candidates with experience and in a management role already. You need to take the degree that best suits your new career path. In this context then the discussion about age is irrelevant.
I hope this helps.
Regards,
Allan Scott
MBA DIrector