Hi! 

How can I lift or decrease the maximum age limit with FMRTE? 

Thanks in advance! 

What do you mean with age limit?

There are certain limitations that are within the national rules

In Germany only professional players can play in league games and you can only get a professional contract with the age of 17. Period

Youth players minimum age is 14. Younger players are not generated by the game.

You can change the age of all your youth candidates to 14 though (so you won't have those 16 year old ones) if that is what you mean.
Just do a mass edit on the new youngsters and set them to 14.
That way they have more time to develop. 

How long a player will play or how long his ability will last depends on some attributes like natural fitness for example but when a player becomes older the attributes slowly decrease by natural means so at some age above his peak he will just not be good enough anymore for professional football

By age limit, I mean age limit within teams. Some teams has a age bar set at 18 or 24 years old. When a player gets older he becomes illegible. Is there any way to lift that age bar? 

No..., not with the FMRTE..., then you have to start a new game, and edit it, in the original editor (pre game editor, from SI), there you can do it, but you can't change outlays of team rules in FMRTE.

gosh darn.. thanks tho

you would have to use advanced rules using pre game editor and edit the fixture rule relating to that comp/squad selection rules