If it was off the tin would be bulging.
The dates on tins are Best Before - nothing to do with safety. IIRC the standard BBD on non-perishable foods is two years after manufacture.
As long s as tins show no signs of change or potential change, they are fine to open years, decades, after their BB dates. If a tin is rusted or bulging, then you do not eat the contents. Not even if you're a student.