As far as I know pregnant women or those trying for a baby who may therefore be pregnant, are not being offered a vaccine not because there's any known problems but simply because it is an unknown. Presumably there were not enough pregnant women in the trials to provide a valid cohort size since anyone who knew they were pregnant would be excluded on ethical grounds from those trials. On the other hand I am sure there have been pregnant women who have had covid with no direct effect on their baby. And yes I know there was a pregnant nurse who died and an actress whose baby caught it but these were the rare ones that hit the headlines.
I suppose it comes down to cost/benefit for you and your baby - would you as a woman of child bearing age benefit from being vaccinated (versus getting Covid 19 even as a diabetic ) balanced against the slight unknown of the vaccine. Given that pregnant women are excluded currently I am guessing the powers that be may think the risks outweigh the benefits of getting the jab as at your age even with diabetes there's little risk from the disease. Incidentally the risks for the aged may also exist given their fragility but the benefits of not getting covid 19 clearly outweigh those risks.