Hello moms. Can you please tell me who started teething at three month…

Hello moms. Can you please tell me who started teething at three months old? Today I'm worried, my gums are swollen and there seems to be a tooth breaking through (like it is). This is our first child, so I'm not very experienced. I can't figure out if this is a tooth or something else. There's no fever. I called the pediatrician, they say that teething at three months is rare, unlikely to be teeth, especially upper ones. In general, write back to me who had their teeth break through at three months old. And how to easily navigate this period. Maybe there are super tips from you.