If you're not a fan of using the phrase "am member" repeatedly, there are a few other synonyms you can use. "Belong to" is a straightforward substitute, as is "be a part of." You can also use "enroll" or "join" if you're talking about actively becoming a member of something. Another option could be to swap out the word "member" altogether, such as using "participant," "affiliate," or "associate." Whatever your preference, there are plenty of substitutes to choose from to keep your writing interesting and varied.