How do you know when it's time...

I'm 23 my husband is 33. We have been married about 4 months Now and have been together overall 2 years. We are so in love and are best friends. We have lived together a year and a half and are working on buying a house.. I feel like I have gotten the baby itch lately.. But the. Part of me still thinks I'm so young but my husband doesn't want to be an old dad since he is 10 years older than me.. How do you know when it's time to start ttc!?