Bus driving has its ups and downs, but even these will differ based on different people's opinions. Terms and conditions also vary wildly between operators, so its not even as simple as just being a bus driver. Some people prefer local town routes and don't like straying too far from their local area comfort zone, where as others hate town work and are happiest on an interurban route. I hate short town circulars or Park & Rides where you spend a day doing the same run 15-30 times in a shift depending on route length as I find them tedious, where as some drivers specifically choose to go on Park & Ride rosters and love it! Some operators/depots may only do Mon-Fri/Sat daytime routes so the hours are maybe longer but more 'normal' working hours, where as others may cover all days of the week from 5am to midnight with the option of shorter shifts but working all kinds of different hours and dealing with a wider slice of society (which can be challenging, particularly of an evening). Personally I like shift work so would hate to be just do Mon-Fri day shifts, where as others would kill for such shifts. Some operators specialise in school runs sandwiched either side of a low-stress quiet set of daytime routes that are primarily used by concessionary pass holders, where as others will do routes that are more intensive and busy driving through tight and congested roads all day. Whether you get your breaks paid or deducted also varies - you may do a 12 hour shift but only get paid 9-10 hours, for example, once breaks/extended layover time is deducted. That adds up over a week when you may spend 48 hours on duty but only paid for 40 or so of them. A spreadover (also known as a split shift) can see your finish time be up to 16 hours after your start time, with a large break in the middle. You can also have as little as 8.5hrs between shifts a few times a week, meaning you might finish work at 11pm and be due back at work at 7.30am - many people may be just going to bed and waking up about those times in other jobs, and as you can imagine by the time you get home at night and have to leave in the morning, the amount of sleep you can get in that time isn't that great. This is a minimum over a restricted number of days per week, but it is legal so something to bare in mind.
As a result, there are so many variables that can be either positive or negative depending on an individual's personal preference, that it is hard to say whether you would or wouldn't enjoy the job and if it is for you. I'd definitely focus on your studies now and not be tempted to slack because you think you know now what you want to do. It could take time to pass your car test and then your bus test, and while there are vacancies galore meaning operators are crying out for drivers at the moment, it would still be good to have good results to put on your CV - not just for applying for a role, but should you find bus driving isn't for you in the longer term.
The job itself can be a thankless task at times. Some operators/councils giving impossible schedules but ignoring drivers feedback, with you instead having to face the brunt of passengers annoyed at the delay (ironically often delaying the bus further while they have their rant at you when getting on). Other road users doing all they can not to get stuck behind the bus, sometimes making dangerous manoeuvres causing you to have to brake hard and then getting a bad score on the on-bus telematics linked to your name, only to then be in front of you for the next few miles ultimately achieving nothing. Buses that leak in rain, buses that get boiling in summer and freezing draughty in winter, and being made to feel extremely uncomfortable if you dare to complain. But it does also have positives - on a good day you'll meet friendly people, maybe be able to help people with their days, possibly get a nice duty with a decent length break for a nice lunch break walk or mooch around town.
If travelling is your thing, after a time driving buses and passing the age of 21, you may then get the opportunity to join a coach company and undertake tour work on the continent. Even just doing some UK coach work will see you visit lots of attractions, often getting free entry and sometimes discounted food/drink. Coaching work does tend to pay less though, and you will be responsible for looking after the group while away such as problems with the hotel, cleaning the coach and its toilet, etc etc. The downside is this can see you spending a lot of time away from home and family, but if doing this while young before you have such commitments then it can actually be quite good. Bus work you'll generally know much further in advance what sort of shifts you'll be working, where as coach work you may not even know what days off you'll have next week until possibly Friday. Again, things vary between operators.
After that waffle though, to summarise I'd say the job has both positives and negatives, but these are very much open to different people's interpretations. If you become a bus driver at 18 and find you don't like it longer term, you will at least have work experience to put on your CV when applying for other things and a proven track record. It is worth bearing in mind that it's not typically a weekday 9-5 job, with long hours, and as such your social life will be impacted when you're possibly working 2/3 Saturdays a month. But it can also be an enjoyable job if you go into it knowing and expecting what comes with it, because you are passionate about it.