To do that there is a quest after the multi story quest. After your cake is done, then you will have to click on it and then click on your preteen and click celebrate birthday. I have a boy and a girl preteen and they can't date sadly but if you want them to date, you have to turn them into teenagers. Then you click birthday cake which will take 1 day to make and you will need 5 lp's.Than they die I guess because I haven't turn any of mine into seniors because they still have so much to live for but yeah enjoy I do not know if pretend can date or be romantic, but they can have a birthday and then turn into a teen.
It is almost like playing with an adult Sim with some simple changes. Make sure your Teenager Sim does their homework and goes to school regularly, and in a good mood.Having a good grade in High School will ensure that you are able to select your Teen's trait when they transition from Teenager to Young Adult.School is also a great place to forge friendships, and maybe even fall in love.And than you can complete another quest at level 27 I think, in order to turn them into adults and get married and have kids (well not by woohooing) but by buying a crib and you'll know what to do from there. Than you can complete another quest and turn them into seniors ... This Sims 3 Guide was originally written for the PC and Mac versions of the game, but also will help owners of the console versions - PS3, Xbox 360 and Wii.