Certified GKH Gardening Expert
This may not be the best idea quite yet! I would wait to see how many tap roots form, as there may only be one. Splitting this will likely kill it, if this is the case.
If there is more than one taproot, then it might be possible without harming the plant. It will all come down to how many taproots form.
This article will help you with the care of parsnips: https://www.gardeningknowhow.com/edible/vegetables/parsnips/how-to-grow-parsnips.htm