Now it will be interesting to see him compete with young talent Joan García for starting goalkeeper spot which could be good for both players and team.
I read somewhere that the peak year for a goalkeeper is above the average players, so I guess 35 years old is still not too old to play as a goalie. I'd be worried if there's no backup or if he's the starting goalkeeper for the next season, if he's way older than that, though. I guess we can only watch whether he'll prove to us that he can still play at the highest level with minimum mistakes, because that's what has let Barca down for the last few years or so. I wonder if they'll try to secure more options by promoting a GK from their academy or signing another one.
goalkeepers have a harder time slowing down their reflexes. This allows them to play comfortably for a long time. The legendary Italian player Gianluigi Buffon played professionally for over 40 years. And he played at the top levels. Therefore, 35 years of age is not a big problem for a goalkeeper if his reflexes are good. If you ask whether there is a problem of producing goalkeepers from the youth academy, I think there is because everyone wants to be a part of the game while they are still footballers. There is one goalkeeper in each team, but you can get promoted more easily in other positions. Maybe that is why goalkeeping is not popular. Therefore, it can be understood that it is normal for players who are getting older to still make high-level transfers as goalkeepers.
Most top teams always go for goalkeepers that's experienced age is but a number in that wing that's why many goalkeepers last in football till they're close to 40 the only thing that would guarantee a youth team goalkeeper some playing time is if he develops beyond imagination then he'll be graduated into the senior team as a second or third choice. Some team even loan them out to inferior leagues to get more experience and develope into the quality they need before giving them the opportunity as an alternative to the first choice.