Yeah I want to do something in data science or modelling so it has value in that, I'm more interested in the application of maths so I'm going down an applied/stats route most likely. Regardless, I've been enjoying studying both subjects since when they have that perfect amount of seclusion in that you don't feel like you're studying maths when doing a computing course and vice-versa but you can definitely see the overlap.
Your other question can't be answered though, its way too open ended and there's so much factors to consider e.g
What career/industry are you interested in? Does it necessitate a specialisation or deeper study of maths?
Are you satisfied just studying computing courses?
Are you thinking of post-graduate options? Do you have an interest in continuing maths?
How will you manage your time?
Is the workload too overbearing for you?
......
For me so far, no idea. I've timetabled my first year to be purely introductory courses and I'm saving Lvl 2 for next year just in case I want to switch to a related degree.