Is my penis small?

mine is 1.5 and 2 or 2.5 when hard is that average for a 12 year old

Why not go through all of the measurements for 12 year olds that have been posted on this site, total them and divide by the total number of measurements. If you really want to get fancy, look at Khan Academy's explanation for standard deviation and see where you stand in the distribution.

You could make it a science project for school. :-)

https://www.khanacademy.org/math/probability/descriptive-statistics/variance_std_deviation/v/variance-of-a-population

I say to be honest, it's quite small. Talk to your doctor.
I know it's EXTREMELY EMBARRASSING but he/she could help a lot!