Question on mimic octopus

Ok, so I’ve only been playing for a couple of months, and I didn’t realize that a brand new mimic had a 20 min cooldown. I play with my son and he asked if I could get him an octopus, so I went to farmers market with what few tokens I had and found a cheap one, not knowing it had the 20 min cooldown. Google hasn’t been helpful in my question, does that cooldown change as it gets older?