I play on Long, but for a certain short amount of time I did turn aging off. I did my best to calculate what their ages would be after a time. The four Cantrell kids graduated High School early and went into Uni right afterward. Problem is, in my own game play I wrecked the timeline. Instead of one year passing for each Term, the kids were on an accelerated path, which meant all three terms were completed in the very same calendar year. Worked out for my young Global Superstar, who made a Clean Sweep of the Big Four Music Awards.
But he was still only seventeen when he graduated, after the fourth term. His sister graduated at the end of the third term and went into the Starfleet Academy. I followed her story during this time, and after her fifth year, she was stationed aboard a starship for her first mission. Since she is the youngest of the first four kids in the Cantrell family, her being now 21 years of age, clearly a YA, this also meant her brothers were 22, 23 (rock star) and 24. When I realized their mother was still a YA, I was like, holy cow, that doesn't happen unless she gave birth to all of them when she was but a teen. So, I changed her age up to adult. I use MCCC to adjust how many days into whatever age level, so that I can maintain the birth order.
As for not wanting the gray hair, take your Sim into cas.fulleditmode and select the color hair you want for them. Joe Cantrell, Sr., is about fifteen years older than his wife, so he's further along toward Elder.
Ah yes, I always have the graduation problem, too. Usually, it takes the kids three to four weeks to finish their studies, and since seasons last at least two weeks in my game, they usually finish within the same year. I choose to ignore this because otherwise it'll get too confusing, especially with rotational gameplay 😁 The nice thing about rotational gameplay, though, is that even when I don't play with a household for longer than a Sim week, I can always assume the kids have already spent enough time at school to graduate.
I've played around with gray hair for my Sim mom, but since her natural hair colour is a very light blonde, she doesn't look all that different. I'm currently considering aging them up just to see what they'll look like and if I can give them their original hair colour back, and in case I don't like it, I'll just quit the game without saving 😁
