Yes, you have to wear a jacket while kayaking. In most locations life jack laws state that anyone above the age of 13 must wear a USCG approved life jacket while kayaking. Children under the age of 12 must wear a PFD
The American Canoe Association estimates that nearly 70% of kayaker drowning could be prevented by simply wearing a life jacket.
That is why wearing a life jacket is highly encouraged when kayaking.
It can take some getting used to. After about 10 min you will not even notice it.
There are fines if you get caught without one, so just do it.
Before you get in the water, ensure that you wear your life jacket correctly. Life jackets only work if you wear them correctly.