For first semester Civil you'll most likely take maths, physics, a general intro to engineering and a surveying class. You should have no trouble getting through this stuff with ext 1 maths. Contrary to what you think you'll likely find the first few weeks or the whole semester fairly easy as first semester is designed to sort of get everyone up to speed and it'll only pick up during the second half of the semester.
It's very easy to fall in to the trap of bad study habits during this time, which is the main thing you should focus on correcting in first semester. Even if you find the content easy, just opening your books for like an hour a day and writing some notes will set you up for success. Establishing good study habits is a must and the quicker you do this the easier your uni life will become. Try and make as many friends as you can, this is pretty important and it's easy when everyone is new. Having people that are going through the same thing you are makes everything so much easier as you'll be able to form study groups and get help with assignments in later years. Don't worry about not doing physics, you'd be surprised at how far your ext 1 knowledge can be applied in actual physics. As far as help goes there are tons of ways to get help if you don't understand something so that really doesn't become a problem just be proactive.
It may be worthwhile getting to know your general intro to engineering professor, see them during office times or something and get on a first name basis as they will definitely be teaching more advanced courses later on and likely be doing research for the uni. Most Uni research teams have to take a certain number of undergrads so it would be worth while discussing what sort of research he/she does and expressing some interest, they won't take a first year but still. Also join any clubs or whatever the uni has, especially engineering specific as you can meet people in the years above you in your degree which can help heaps with getting past exam papers, assignments and notes. Uni events are fun as fuck, our degree regularly organises pub crawls, wine tours and scav hunts. Basically if you do all that you'll not only do well but most likely enjoy it too.
