What age for a 3 mth a year visitation schedule .....?

my son is almost 18 mths.I was his primary caregiver for the first 8 mths of his life,but he has now been with his mother for the past 9 mths,with the exception of a one,20 day period 4.5 mths ago,where he was with just me for 20 days.He seemed very happy with me during that 20 days.I am now adressing a regular vistation schedule,but,i am concerned about how this will effect him.He is only 18 mths.I want him to keep a bond with me,but his mother tries to have me arrested almost every mth,and she refuses to discuss any vistation at all,so my moving up where she is seems like she would just have me arrested.I work from home,so he would be with me always,and i am thinking to have him come down in June for three mths ,as is what will most likely be a permannet visitation schedule eventually.He will then be two years old.Is that too young?What age is a good age to start such a schedule?I would rather his mother just come back home,on what ever terms she demands,but she just wants me completely out of my sons life,partially because of money problems,but mostly because she is simply jealous,due to post pardem.