If I have mosaic turner's syndrome will I have premature menopause?

Turner syndrome. Turners syndrome is one of the most common reasons for premature ovarian failure. Many turner syndrome patients will never menstrate because of rapid follicular depletion. Since you have a mosaic pattern, it is unpredictable when your ovaries will fail. You could potentially start menstruating and start ovulating for a few years before ovarian failure.
Possibly. Mosaic turner's means that you may or may not have certain features of turner's syndrome. If you're 46 years-old, however, normal menopause can start at this age also.