When to start ttc

Haylie
Hi. I have a 2 year old son from a previous relationship, I am 24. My SO is 25 with a 5 year old daughter from a previous relationship. We have been together 4-5 months and have known each other for years. I am so broody and feel like my body is telling me it's time to have another baby. We are both financially stable independently. I have tried so hard to rationalise with myself and try to stop this feeling. When do you think is a good time to either bring up the baby convo or to actually start trying?