The Sims 3 is by far my most favorite game ever! I love it so much. The only reason some people rate it for teenagers is because you can have sex but it is called 'WooHoo' in the game. But this is censored and done under a bed. This game is very realistic, you can also make your sims use the bathroom and have a shower; which is once again censored. It is kind of like a survival game, as in making sure your sim is satisfied and has a happy life. You take care of them like your children. You make sure they eat, shower, go toilet, go to school; etc..
Yes, they do die eventually. It has happened to me before, when my sim drowned. There is NO blood or anything, they just disappear and turn into a ghost. And then the grim reaper comes and puts a grave wherever your sim died. But it is unlikely for that to happen.
If you make your sim woohoo a lot, the female does eventually get pregnant and have a baby. You do not see the birth at all. This is okay if your child knows where babies come from.
This game is great if you like building, too. You can design your home and decorate with endless possibilities! You can get very creative :)
Overall this a fun game and so great to play :D I really recommend it!