When someone takes credit for your efforts....

I've been in my current position for about a year. I took a position in a growing company while I finish my degree, with hopes that I can obtain a position in my field as the company grows and increases positions. While in my current role, I've contributed to my current department's successes in various ways. I've only been here a year, but my efforts have directly increased productive communication between departments and customers. I've also cleaned up and clarified some processes. I'm dealing with someone taking credit for my work. This person has been here for years and confronts all change with opposition. Yet here she is trying to take credit when my proposed changes are successful. I realize I'm part of a team, but I would like credit for my efforts.