If you believe in the core principles of feminism and have dedicated your life to living those principles as much as you can and teaching them to your children and others then you are a feminist.
Lot of women call themselves feminists who aren't really walking the walk, you know what I mean? Especially since the corporate machine latched on to feminism as a marketing plot to sell product.
They're the ones who made being a feminist "cool". Before then, there was no status points to being a feminist. You were generally looked down on and mocked.
Once it became "cool" though, you have the same dynamics being engaged in you always have about "IT" factors. People will steonon and start claiming who can be a feminist and who can't.
And it's usually that type I described above making such proclamations.
Anyone who makes feminism a popularity contest doesn't get the point of feminism.