Mathematics and philosophy have had a long and intertwined history together. Ancient Greek philosophy is resonant with Euclidean geometry. The great Continental philosophers Rene Descartes and Blaise Pascal are as remembered for their contributions to the development and advance of mathematics as for their philosophical achievements, as is Leibniz. In the analytic world, figures such as Bertrand Russell and Alfred Tarski are noted for their work combining mathematics with the philosophical field of logic.
So mathematics is clearly relevant to philosophy. But the connections are not always direct. Given that, it is not as clear that studying mathematics would definitely aid the study of philosophy. It's also worth noting that contemporary continental philosophy is not particularly mathematical.
With that said, if you have an interest in mathematics now, and in philosophy later, I'd see no reason to discourage you from combining your passions. You'd certainly be following in the footsteps of some of the greatest practitioners of either field.