If i had a breast mri last year for high risk screening and now i have to repeat it annually, is their a higher likelihood it will be negative this time since last year it was?

Yes: Yes, because last year's MRI would have picked up anything suspicious(97-99% sensitivity) in your breast that had been present up until that point, including slow growing cancers that might have been present for years, and since there was nothing, this year's MRI could only possibly find cancers that developed since the prior MRI(interval cancers).