Pregnancy is not the only cause to miss a period, consult a physician.
Some women do not have regular cycles, so 60 days is certainly possible. Professional sports players also often stop menstruating because their body is conserving energy due to a taxing exercise schedule. So there's no simple answer, but if you miss two regular cycles, I would definitely take a test.
Like the above reply, some women do not get regular periods. It all depends on your lifestyle, it also depends whether you are taking mediation. Some medications can make your periods irregular, having a period every 3 to 6 weeks