I think maybe just see how you go...
I wouldn't say it's something you need to plan this early, a lot of people make that decision at the end of their second year. Personally, I was a mature student (24 when I started, just graduated this year), and I know a lot of people who made the decision to take a year out, but I myself didn't consider it. Being a mature student I actually found helped me in a lot of ways because I had taken that time to really think about what I wanted out of uni and was doing a course I really loved and knew was right for me, and ended up often doing a lot better and finding it a lot easier I think than some other people on my course who had come to uni straight out of school and had chosen that course because they were good at it at A levels or didn't really know what else to do.
In all fairness, my last year was quite rough for a number of personal reasons, chief among them the fact that the summer between my second and third years was incredibly busy and I returned not feeling rested and just couldn't find the space or time to decompress during my final year which I desperately needed, but I still made it through and, broadly speaking, it was fine. I'm even choosing to start my Master's this autumn, and I've just been making sure I really relax and take care of myself over this summer and I feel so much better for it.
I wouldn't say that third year wasn't any more difficult mentally than second year, it was really just over the second half of that year when all the deadlines hit and you're just very very busy. My advice would be to take each year as it comes and just see how you feel at the end of your second year. Take every moment you can to rest and take care of yourself in between (especially summer holidays, but also just like reading weeks, and half terms and weekends and stuff) because if you're taking care of yourself there's no reason you would need to take a year out. And, if you do reach the end of your second year and you're really burnt out and feel like you need a break, then I would again gently recommend prioritising rest rather than jumping into a new high-intensity project because you won't go back to school feeling any better if that makes sense.
I obviously don't know the ins and outs of your course, but I feel like drama generally tends to have higher contact hours than a lot of subjects because obviously you need to be in a class acting, and this might be something that affects you in which case I think just adjust as needed. As an autistic person, I always found contact hours very draining because my social battery is basically always on 1% and so that had a big effect on me in my final year because, like I said, I was already quite burnt out anyway (and I was even doing English Lit which basically has no contact hours to begin with lol). But you might actually find that kind of social experience really energising as a lot of people do. Or it could even be some other thing that I haven't thought of that affects your motivation either positively or negatively, so I think it's a case of just seeing how you feel once you're in the flow, and just like tuning into your needs.
Obviously this is all based on my own personal experiences, and you might feel very differently than me, but I think my main point is to just not panic about how you're gonna feel in two years time, see how it goes, and just keep checking in on yourself and listening to what you need. Hope that helps x