How long should I wait?

I recently purchased a 4 month old chin male and he is getting adjusted to our home and was wondering how long before I introduce a female to him and should I look for a older or younger than him female I want them to bond and know to introduce slowly and all about breeding from being a CVT but was curious with other chin owners have dealt with and what their experiences were. I want to have the intro go as smoothly as possible. I have had 2 male and 2 females all coexist but they were close in age and already bonded. Thanks in advance