As the previous poster said, you really have to find out it your employer will give you adequate insurance, private insurance for someone with T1 will be impossible/prohibitively expensive. Some of the big companies would be able to obtain cover, that's how it works in the US.
(Even moving to most places in the EU the problem can arise for people who are not working and thus now need to obtain private insurance for a few years; people with chronic (expensive) conditions find they can't get the necessary insurance)