Each person's Sim is in The Sims 4. They will behave like real Sims. They have feelings too. But the user becomes a Sim character. They can have any kind of mood. They must be properly cared for. But some Sims are fun, some Sims are hot-headed, and most often friendly. But if you are 2 years old They will be in their toddler years. If you are 7 years old You will go to school. If you are 18 years old You have grown into middle school age. If you are 20-40 years old. You are in adulthood.