@Donna1 it depends on your blood glucose levels. If you are suffering with high blood glucose levels as a norm, then yes, your immune system may be compromised and a t take a long time for illnesses to clear up. If you maintain a more normal level (sub 7) then they typically take no more time than anyone else, at least in the experience of me and many others on the forum. Just because you have T1 doesn't mean a rubbish immune system.
What I'd note about the last couple of years is that colds have generally been taking longer to clear up (just looking at my non-diabetic colleagues) so I wouldn't necessarily put it down to your diabetes myself.