Spur lenghth is usually the way most peope judge turkeys age ... but as mentioned terrain can effect the spur length ... get a bird living in rocky terrain and the spurs can really be worn down.
As far as tracks, if under 3-1/2" it's a jake and over 3-1/2" probably at least a 2 year old.
Beards can break off sometimes due to cold freezing weather, insects or mites, etc.
Easiest way to gage whether you're getting a mature tom versus a jake, as already stated" is the length of his tail feathers .... even shaped fan, tom ... 4 longer center feathers, jake.
Nothing wrong with harvesting a jake as your first bird ... you can get more than one tag!

Nothing wrong with harvesting a jake