Would an internship here help me become a journalist?

I'm not even sure you need the reurance, given how carefully you seem to have thought through how to make this work for you, but here you go: it's a great opportunity, and you should take it. One other thing you might want to consider if the opportunity presents itself is volunteering to help with social media projects; older staff don't always have the time or the insight to use those effectively, so they might welcome help, and they look good to employers. Also, being a Senate intern gives you access to a circle of alumni who have done the same thing, so if any of them wound up in journalism (and I'm sure several have), use the connection to reach out to them.