It looks more like mold to me; perhaps that soil was wet before and also poor air exchange. I guess you bought it like that?

If you are repotting anyway, old soil should be off the root ball. Plant in well draining mix.

Yes, it's a mold and it won't hurt your plant. I had some plants sitting on a vinyl covered shelf. Some of the heavier pots made depressions in the vinyl and although I had gritty mix and a well draining pot, it sat in some moisture. And my summers are quite wet.

Thank you Rina and Crenda!

Not an issue. Sometimes, I have a toadstool come up beside the plant (yellow colour). I don't bother to remove the molds.

S G - I thought it was just me! LOL I've been learning a lot about fungus. I do remove them so they don't spread everywhere.