Do it now, I assume its relatively bare? I like that they have a little time to figure out where to send the spring energy, rather than be interrupted by cutting after the rise has begun and the energy is wasted by having been sent to points that get removed.
Basically a newly planted rose, has already to some extent been pruned. So, apart from perhaps tidying up any damaged ends, leave for a season. Then begin to shape the plant. So yes, now is a good time to start pruning.
Its a good opportunity to study how to prune a plant open, controling the crosses and other details, then sit back and watch them explode. If they are not vigorous as spring springs, immediately suspect drainage and soil issues and move to remedy the problem.