MPP SOP advice

[mpamppquestions]

I posted this in the government affairs forum, but figured I would as well post here for additional input:

My background: I have been working for an environmental advocacy non-profit organization for over two years doing fundraising, social media writing plus some general IT stuff. I studied English literature during my undergrad. I am applying to MPP programs (CMU Heinz is by far my top choice and I am very anxious to get in here) to study environmental policy, and ideally would like to work for the government or a think tank doing environmental policy analysis. I am struggling with telling a compelling narrative that shows why I am a good candidate; I have been around a lot of environmental regulation/policy from an advocacy perspective, but have virtually zero experience doing any analytical work. I believe my work experience at least shows commitment to my area of interest, but I am worried that only having experience in this field at a mostly tertiary level makes me a weak applicant. Also, is coming from the non-profit sector and going to grad school to break into government jobs a common narrative among applicants? Thank you to anyone with any insight.