More Awesome Than You!

I created a family with seven toddlers and one adult for a challenge.  On the last toddler day I got five to the cake before 6 o'clock. 

After 6 o'clock one of the sims aged to a child on his own.  The last one was carried to a cake and aged to a child.

When it came time for the next birthday, I noticed only the first five were ready to transition.  They had "1 day left" until teen.  The two that aged after 6 o'clock had 2 days left.

Is this normal?  It was unintentionally hilarious, since I created a set of identical twins.  Now one is a teen and the other is a child.

Thats normal.  You lose a day when aging sims before the automatic transition.

If you want a party and don't want to lose a day, give the party after 16:00h or so so the age transition will come during the party.
Wait until the Sim begins to automatically transition and immediately force-error any of them. That will reset the aging controller and give you ample time to bring them all individually to the cake/have them blow out candles.

Oh that's clever Jordi! - I've had so many birthday party disasters because the sim aged before everyone gathered round the cake that I don't throw them any more!

You know you don't have to wait until 6pm to blow out the candles, ay? I make my sims do it well before 6.

Thanks witch - yes I do know you can transition them early, it's just one of those things that I always leave too late.  When the kids get home from school at 3, I like to up their motives before the party and time just gets away from me.  I either have them go to the cake too late or else they are stuck in some other action and can't get to the cake.  I do find all those influence wants a real nuisance at parties - you can't concentrate on making friends because you don't even get the throw a good party want until you've done lots of stupid influencing!

If you do it before 6pm, you lose a day of their life.

That's good, they live too long anyway.  ;D

Pescado once told me that sims can't age (or die) while sitting or laying down.  Transition always happens on the hour, so you only have to make sure they're busy right then.  Toddlers can't grow up as long as they're in the crip, so just carry them directly from the crib to the cake, and make sure the hour doesn't turn on the way.
I don't usually bother with the cake, or parties, I just let things happen when they happen.

Thanks for all the replies.  I'm relieved that this is normal, and not some horrible glitch waiting to destroy everything.

I'm actually enjoying the non-identical identical twins, so it worked out for me.