About waiting between your next kid

Serene

I plan to have 3 kids. I had my first 3.5 months ago. Now that I've survived the newborn phase, am i ready to do it again twice more? Am i being too naïve in thinking that i want to get the hard newborn parts over now, especially that im younger than i will ever be again? Many people are telling me to wait 18 months between my kids, but i am afraid if i wait that long, im going to be so new to it again when i give birth. I went through PPD and want to avoid it in the future.