Do not follow all the information you see on YouTube Frogerz most of it is false or not proper husbandry.

Danfrog and Lija have on a good start. Your frog is still a baby. At 1.5 inches it is propably about 3 weeks out of the water IF it was cared for properly by the shop where you purchased it from.

You need to offer your frog small crickets daily. Dust the crickets with a reptile/amphibian calcium powder with Vitamin D3 every other feeding and once a week with a reptile/amphibian multiviatmin. Do not dust with both calcium and multivitamins in the same feeding. Offer as much as it will eat in 15 minutes. Don't keep trying to touch the frog you will just stress it out. They are look, but don't touch pets. They should only be handled when absolutely necessary.

If your frog is cared for well will reach adult size in close to 5 months time. Some grow much faster and can reach adult size in 1 to 3 months. This all depends on genetics and poper diet.

Welcome to Frog Forum.

Any further questions feel free to ask.