I'm planning a similar trip to Scotland this summer with my friend. We're not that much older than you, either (both 18), but we've been backwoods camping for years and feel confident enough in both our kit (and, much more importantly, our ability to use it) to head into a different, wilder, environment. But even so, we will be taking kit that we wouldn't ordinarily think of taking; water purification system, stove, decent shelter (I usually pack a basha just in case, but I rarely use it instead of natural shelters), and a bivvy bag. The trick is to err on the safe side in all things; some might say that this is the golden rule of bushcraft! Your kit, as has been said by many people much wiser than I on these forums, should match your ability and knowledge; not to contradict the others in this thread, but you could very well go to Scotland and have a great time if yout took the right kit for your level of experience... but this kit might very well include a campavan if you're new to the game!
But yes, I do agree with those that have posted before me; stay closer to home for the time being and work on your skills! You'll soon find what kit you need and what you don't, and then you'll notice the amount of kit that you need reduce in size naturally as you replace item after item with your own hard-earned knowledge. Your experiences closer to home should not only be a lot safer, but I have no doubt that the satisfaction gained with every new skill will be an awful lot more enjoyable than a few cold wet nights at the foot of an unfamiliar Scottish mountain!
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