@Eylise - first, an early Happy Birthday!
Sure alcohol is difficult because it messes with the glucose dumps from your liver. But that doesn't mean you can't drink.
First, make sure your friends know how to recognise a hypo and what to do about it. Sure, they will be drinking too but there is usually one person in the group who is a little more sensible than the others and you probably know who it is in your group. It could be useful to give them some spare hypo treatment.
Next, consider what you will be drinking. The problem with beer, cider and some mixers is that they contain carbs. I don't mind drinking these and carb counting/bolusing for them ... at first. I do this to avoid the highs and trying to work out what to do about them.
The other option is to drink wine or spirits with sugar free mixers so you don't have to worry about carbs.
My approach is to either drink wine so I don't need to bolus or beer and bolus for the first couple of pints only as the alcohol will bring down my BG anyway when I have more to drink.
If you get a chance, some food will be useful. When I eat, I use my normal correction dose and target if I am high but lower my carb count by about 25% to 50% (if there are 50g carbs in my meal, I will only dose for 25 to 37g carbs depending on how much I have had to drink at that stage) so my bolus is less than usual.
Finally, bed time.
When I am not drinking, my bedtime target is between 5 and 6 mmol/l.
When I have been drinking, my bed time target is around 9mmol/l. I will correct a high BG to bring it down to this level or snack some extra carbs to bring it. I do not correct at any other time in the evening.
The other thing I consider is that as my liver is busy dealing with the alcohol and can't do anything much else for the next 24 hours, I reduce my basal dose by about 25% to reduce the chance of hypos. This is easy with a pump and not too difficult with a slow acting injection - I just inject 25% less than usual.
This is what works for me. We are all different. We are used to different amounts of alcohol and willing to take different levels of risk.
My advice would be to take it easy but have fun.
And have an amazing 18th birthday to remember.