7 month old is too young in my opinion. I started my son at 5 years old on Deso. 4 years old on flat rivers.
Deso will be very hot and windy this time of the year. Which means you will need to get going VERY early in the morning and bake at camp in the afternoon. Babies don't do well with heat usually. At this flow, you will have long days on the river rowing against the wind.
Rapids at this flow are much more technical, a lot more rocks are exposed. Any swimmer would most likely get banged up good on the rocks.
I'd personally leave the baby at home for a couple more years. Make sure your kid knows how to stay afloat and comfortable in a life jacket for a long time (and helmet).
Take this time and make your boat family friendly, so when your kid is ready to go so will you be as well.
Family friendly boat: Bimini, easy access captain boxes for snacks and putting away hats/clothes quick. Comfy paco pads on the front. An easy accessible box/bag of toys. Make your gear pile flat, so it's easy to walk around your boat (kids don't sit still). Proper weather gear for kids (I usually pack dry suit, shorty and long wet suit for my son). Kid games at camp (bocce, ladder ball, horse shoes). If you have a girl a tent pee bucket with a lid (your wife will love you for that
Hope this helps you, but when you are ready to go, Deso is a great kid river with large beaches, fun rapids and pretty scenery. As Hunter said, most rapids are easier ran than walked. Joe Hutch is the only one you can walk it easily, but it's too fun to bypass for kids.