Natty,

Once you have your equipment bid you can email the training scheduler to request an earlier or later start date relative to others in your class.
As others have said, they are extremely accommodating to life events. As of day 1, you are a United pilot on the seniority list. If you have to take care of business at home, they will let you do what needs to be done, then when you are ready they will bring you back to finish what you need to, no Huhu.