At least at my company, there isn’t a hard requirement for having previous digital marketing experience to get a digital marketing job. I mean, especially when you have existing marketing experience, so that’s a leg up vs other applicants who lack that.
However, I would try to gain real-life digital marketing experience to supplement what you already know and can study for. For example, if you want to focus on websites or analytics. I would take classes on those subject, and/or try a few personal projects that will get you familiar. If you want to gain further experience, look into volunteering for non-profit organizations. There are many that would love your help in digital marketing, even if you aren’t a pro at it yet. You can then use that experience to help you get a digital marketing job.
Wish you the best!