Your Tama isn't growing faster than usual. That is the rate that all Tamas grow at, unless you debugged your Tam and are fast-fowarding it.
When your Tama is first hatched, it is 0 years old. An hour later, it grows into a toddler. The next day, when your Tama is 1 year old, it grows into a teenager. Depending on what time of day your Tama was born, it can grow into an adult at age 3 or 4.