harder time believing that it’s 20 cm long than 19 cm long

In December, I (M19) measured my dick after not doing so for a while and came to find out that it hit the 20cm mark (nbp, bp is 20,5cm).
Before that, I had been at 19cm for a while and had no problem believing my measurements but for some reason now I find myself not believing my size, sometimes remeasuring, etc.

I hope this is the appropriate space to share this, lmk what y’all think