There's a lot of considerations and there is no right answer. I for one am currently on a non-law degree, and kind of wishing I had done law, but I also have friends on law degrees wishing they'd done non-law. Other comments have covered the pros for non-law, and I agree with all of them, but I'll cover some of the cons.
1) Time and money. This in my opinion should not be your biggest concern at all, but still worth factoring in. As a non-law student, you will inevitably have to do a law conversion course, in addition to the SQE. While this isn't a requirement by the SRA, almost every major firm still requires it. This means after your 3 year degree, you usually have to undertake a year long GDL (law conversion course) and then a year long SQE prep course and sitting exams (like all law students do). So that's an extra years study and funding. If you can secure a TC beforehand, they'll often fund it for you though.
2) Timelines. The timeline for a non-law student is a little different, and more difficult if you ask me. A law student (in the best case scenario) applies for vac schemes at the start of second year, does vac schemes in summer after second year, and secures a training contract at the end of the scheme, before starting their third year. A non-law student, generally needs to wait until third year to apply for vac schemes (though quite a few are now offering to penultimate years too), meaning a more stressful final year, uncertain future, uncertain funding etc.
3) Resources/Opportunities/Networking. This is one of the bigger challenges as a non-law student I think, and that's simply not knowing what you're doing. I remember being extremely shy to join the law society or get involved in mooting or anything like that because I wasn't a law student, and didn't know anyone. Tbh I'm still not really that involved. It's one thing to say "oh yeah I'll join the law soc and get invovled" and another to turn up to a social full of people who are all on the same course, and are in their friend groups. Even beyond the law soc, you're just so removed from the legal world as a non-law student, you have to make a really conscious effort to research these things and seek out events, and keep on top of everything. It can also be a little isolating, if none of your friends or course mates are interested in pursuing the same path.
Don't let this put you off. I think the number one thing is studying something you'll enjoy the most. Uni can be hard, and even harder if you're bored. Probably the single most important thing for you is getting a 2:1, which you're much more likely to do if you're enjoying yourself.