There are quite a few different websites which provide free psn codes that you could use to play your games within the play station network. Neither would your age nor would your gender matter a little bit here as gaming is something that everyone would enjoy to you. The only time that it may matter is when you have your own priorities to look after.
Everyone would have their own priorities to look after and their own ways of sorting things out. Adults tend not to have as much affinity for games as would kids, so it does make a huge difference here.
Anyway, regardless of what your purpose of going for psn codes may be, there would only be limited ways in which you could be getting them.
If you need PSN codes for free, you will have to either fill in some surveys online which tend to be short and concise. These are the requirements set by free psn code providers as they also need to get something in return for providing you with psn codes. They are not obliged to make rare stuff available for free to anyone, as they could be selling them if they wanted to. An example of such a site is http://www.stillnsync.com/free-psn-codes-psn-codes-generator-100-working/.