iphone 5c has not been backed up 244 weeks

iPhone 5C is an outdated iPhone, can’t be update to a higher iOS.

iOS 10.3.4 is the latest iOS version for iPhone 5C.

See this Apple article: If you forgot your iPhone passcode

If you forgot your iPhone passcode - Apple Support

Also, depending on which carrier you're using it is either useless as a phone now, or will be in the very near future.