Asian Pear Tree Pruning Question

Hi,

I'm new to planting fruit trees. I've two Asian pear trees in my backyard. I've them for four years now and have never done any pruning to them. I just ran into the article regarding pear trees pruning for the first four years to help it grow healthy and craft it to have three strong primary branches. Both of my pear trees have never been pruning, one is in the four years and the other is in the third years. My question is will I able to prune off some of the branches below two feet this late in the spring or would I have to wait till next years in late winter to prune off all the limbs that's below two feet? Any help or suggestion would be greatly appreciated.

Thank you,

T.L