Baby #2 ?

I Have a daughter that is about to be 1.5 in a few days and while I was pregnant me and my husband said it would be a good 5-10 yrs until we had a 2nd but now we’re debating on having another already but we’re not too sure if it’s just because everyone around us is having more kids so we feel it’s our turn or not. I really do want another but also want my baby to be the only one still but want her to have a sibling as well… how did you know when you were absolutely ready for another baby ?