If you kept it in a heated garage... then you did enough winterizing.
Well... the oil change is up to you. It's 100 hours or one year... so, if your boat hasn't seen one year of use yet... then no, you don't have to change the oil. BUT... I would change the oil since it's been sitting dormant.
With my bikes... once winter is over... I will put one ride on them, and then change the oil, regardless of how many miles they got the summer before.