Bryan's puppy has been gaining weight for the last day of the graph shows data but the puppies way over time which is reasonable inference for the weight of the puppy at 3

Generally, larger dogs take longer to reach their adult weight. Small dogs will be almost fully grown at around 10 months old, while really big dogs will continue to grow until around one and a half years old.

The food your puppy is eating is very important for it to grow. Make sure you're giving your puppy a balanced diet with all needed nutrients.

If your puppy doesn't gain weight as it should, it may be best to contact your veterinarian.