Accidentally ate a really mouldy cinnamon roll (white mould)! dangerous? if i was to get sick, how long would it take from eating the mould?

Possible: The danger is small, but real, as a small number of mould species produce toxins called mycotoxins (fungal toxins). Even if present, unless conditions were just right, no toxins may have been formed. Most cases recognized have occurred by ingestion of foods made from contaminated grains. So, it is unlikely that you will have any ill effects, impossible to say when.