Introducing kids

I (40F) have kids who want to meet my (45M) partner. My divorce was six years ago. Kids are 13 and 9. They have no problem with their dad’s partner. They are well-adjusted kids. Everyone seems happy and has been happy for a long time. Most online advice says wait six months to a year before introducing new partner. Any specific reason to wait? Everyone feels ready for this after four months. Kids want this. Please give me the bad, the points I’m blind to.