Honours is pretty much focussed on how well you do in your third year subjects. You would probably be looking at needing to get 75+ at least to qualify for honours in actuarial, if not a little higher to be safe. I wouldn't stress too much about first year. It's not really that big a deal. Realistically It may effect your ability to get internships as you'll be applying for them in your penultimate year, but three things 1) If you're planning to do honours you'll be applying at the start of third year, not second year so that gives you extra time, 2) you do have one more semester to bring your marks up 3) marks aren't the be all and end off for getting a job, having good extra-currics and being a nice person are just as important
Also don't stress too much, you might just surprise yourself when results come out, for the traditionally insane subjects actuarial kids take like accelerated math will have marks bumped up bigtime.