Welcome Lynnster! Always nice to have the other 50% represented here. Out of curiosity, what was it that attracted you to the CB?
About those mirrors. For me they just look "period correct". Chrome/round says 60's or very early 70's and complement the look of the STOCK bike. Start to make some major changes to your bike and then other mirror shapes/finishes/styles will come into play that will complement the look perhaps better than the stock ones.
I would just say keep in mind that you have a ROUND headlamp that says 60's/very early 70's and depending on what shape mirrors you choose (say rectangular with sharp corners) that could scream 80's. This would be very confusing for us OLDER guys seeing a Led Zeppelin era headlamp and Flock of Sea Gulls decade mirrors on the same bike.
I happen to like the stock mirrors for a couple of reasons. They're well made. My bike is very mildly farkled and they don't look out of place. Plus those mirrors have never moved or vibrated one iota while riding for almost 10K miles. I have broad shoulders and the stems are fairly long and they help clear my shoulders even when wearing an armored jacket. Course, depending on your height that may not be needed and chrome seems to fall in and out of favor a lot.
Obviously making the bike your own is a very personal undertaking and something the CB platform actually makes very easy and almost encourages you to do. Lots of good ideas on this forum. Lots of good people. And lots of good looking bikes with aftermarket mirrors here as well. Whatever you do, post pics!!!