So me a and my boyfriend have decided to have a baby

We are both parents, both have kids from other relationships, me 3 and him 1.

Im kinda scared to start.

Me and my ex tried to have another one before we split. We tried for 2years and nothing.

Im scared of getting my hopes up and always thinking negative.

Im sopose to get my period and 3day and im keep saying im going to get it while my SO is so positive.

Any tips on how to get pregnant lol

Thank you all