Lisa,
First off: Welcome!
The CB350 is a great bike for a beginner or a seasoned rider. I have been riding motorcycles for almost 20 years and I enjoyed my '72 CB350. A fun bike to ride!
What year is your bike? If you have any questions, feel free to ask anyone here and don't forget to check out
www.hondatwins.com.
I got my Cb350 a rusted bike with a siezed engine that was nearly ready for the junk yard. Completely restored the bike and then sold it six months after getting her done...needed a new project! So, if you need parts, I've got a lot!
I read that you plan on lowering the bike. Might I recommend lowering the seat first. If the bike is near stock, get a different seat pan to keep the integrity of the stock bike. Use new foam and gel pads to get the right cushion while keeping the height lower. IF you decide to lower the rear end, you'll have to ensure the rear tire isn't rubbing in the rear fender. Also, going with new shocks may require you to remove the chain guard as some shocks are thicker than factory shocks.
Futhermore, if you lower the rear end, you will need to lower the front end to ensure the rake/trail angle is maintained. Changing one end without the other can adversely affect the steering geometry... lowering the rear end would be like stretching the front end...it would make the steering a little less responsive at slow speeds.
Good luck on your new ride and.... as we say in the biker world "Keep the dirty side down!"