Your "friend" is correct. One major part of breaking an engine in is making sure the piston and sleeve have been heat cycled multiple times. The goal is to get the piston and sleeve to 200F then allow them to completely cool with the piston at BDC. You might hear varying opinions but this is the most common approach to breaking an engine in. I always cycle my engines 4-6 times on a starter box, in 3minute intervals, then run 4-6 tanks gradually tuning for more power.

You'll be ok though. I always look back and really appreciate the knowledge I gained from my first engine. I blew three of them up though............but I learned a lot. Now, I am totally comfortable handling a $400 engine.