You should be okay to repot it now. Depending on its parentage, most hybrid cymbidiums are (or soon will be) starting their growth phase for the new year. So repotting your plant now would be the best time to do so. Getting it established in its new home before the heat of summer gets here is especially important. As far as the size of the pot goes, that will depend on the size of the plant itself. Does your plant have lots of healthy white roots snaking around the interior of its current pot? Are the newest growths growing against (or near) the side of the pot? If you answered yes to either (or, even better, both) of these questions, then it's time to move it into a slightly bigger pot. Congratulations on your new plant. Cymbidiums are pretty forgiving plants (within reason
).