I'm not in school yet but I want to intern as I'm going to college. The issue being, they want you to have at least good knowledge on the programs, which is understandable but means I cant gain experience.
Most companies hiring interns know this, so don't worry! Though an employer will usually want you to be at least a little familiar with the field you'll be interning in, most companies will not expect you to be an expert, and how could they?! When companies are hiring interns they're probably expecting to teach you a lot about the field you're going into. Honestly, there's a ton of internships out there that are really only focused on teaching and impressing you, just so you go back to that company as a full-time employee!
With that said, a lot companies hiring interns are usually looking for people who show initiative and can help get things done. Maybe a way that you can start taking that initiative is by looking up companies you'd like to intern at and just try to learn about their intern programs. Not even to specifically prepare for that internship (though that's a good idea), but because hopefully it'll take you down a rabbit hole of similar internships, and ideally, it'll tell you a little more about what those jobs are like. Then you can start assembling a list of internships that look enticing to you, and hopefully through doing that research you can speak a little more to what the jobs actually entail. From there, just try to apply to those internships, and then really sell the interviewers on your ability to get started on your own (as per the research you just did) and try to find the aspects you're passionate about and really drill down on those.
So in summary, don't worry about your lack of experience, and just dive in!