Yes, you can make your herbal tea with fresh rose hips. Although, rose hips have so much more flavor and higher vitamin content if you wait to pick them after the first frost.
Make sure you split the rose hips and remove the seeds with all the fine hairs before making your tea. You don't want to swallow the hairs. Just steep one or two tablespoons of rose hips in a cup of boiling water for about 10 minutes. You can sweeten with some honey or add a few sprigs of mint to give a different flavor.