If I was planning to move to a development like the one you are considering marieeliz I would want to know, as Jane says, about the management charges and whether there will be a residents committee that have a say in how / where the money is spent. If you are allowed to take your dog, will you have your own fenced garden or is the development open-plan? Do you get your own designated parking place and will there be spaces for visitors to park, too? Who maintains the paintwork on the outside of the building?
If everyone is over 55 you shouldn't have a problem with rowdy neighbours, though you never know!