Either way, there are plenty of precedents. The number of fully-recognised independent countries has grown from 79 in 1900, to 103 in 1950, to 194 today. Some 30 of the countries that have gained their independence since 1945 did it by way of a referendum.
Unionists routinely use adjectives such as “unprecedented” and “irreversible” as part of Project Fear. However, the waters are well-charted, the road is well-trodden and there’s a plethora of road maps to choose from. That’s the very beauty of it all.