I don't think there is an age limit, but I don't know if he wants to be the president one day since he has so many other distractions elsewhere (Kosmos, Davis Cup, FC Andorra etc.) and whether he can dedicate full time to the club.
To be honest I think those are preparations for his presidency, not mainly, but they certainly help. He's building up an enormous network of contacts through his company, so funding for his candidacy won't be an issue.
And Andorra is just a way for him to get some experience in business side of a club.
Being president for Barca is a relatively short period of one's career anyway. He'll still have the opportunity to continue his other projects after having been president and eventually replaced by the liberator Riqui Puig.