It sounds like a good first try. I canned peaches for the first time without the help of my Mom last year and decided I'd do cold packing to skip a step. After boiling there was 2-3" of emptyness on the bottom of each jar! I switched to hot packing after that first batch...
If you're cold packing, it's because the peaches cook down when you boil the jars. If you're hot packing, it's normal. You can only pack so many peaches in the jar.