The terms Vintage, Classic, Antique.... have been defined by a number of organizations over the years, but the definitions are not very clear.
Most clubs use vintage as a catch-all for any bike which is old enough to qualify for inclusion in vintage shows or rallies, rather than classic.
It's a moving target. The English have the strictest definitions for different eras of old motorcycles, while in the US there seems to be a lot of cross-over, if not outright confusion over the terms.
Your Suzuki is probably best referred to as a Classic, although many of us older guys might take exception, since classics to us, are bikes that were built if not by, the British motorcycle industry during their classic period (1950-1970, give or take a few years on either end), at least motorcycles built during that period wherever they came from.
At the other end, we have antiques, veterans, pioneers and vintage. Some of which are names only used by the UK vintage clubs. All except vintage being built before WWII.