I also had not received any vaccinations for many years, but I was not concerned at all getting the COVID shot. I figured, at worst, I would get a brief headache or feel tired. Ultimately, I could not even feel being stuck by such a tiny needle (I used to donate plasma and they use a much larger needle) and I experienced no side effects other than a slighly sore upper arm for a day or two after each shot. Getting the two shots was a nothingburger experience. Now I am likely protected against any severe COVID symptoms if not completely immune. Getting the shots was an easy choice for me.