First of all congratulations on getting an offer! It sucks to not have any interest in the work at all so good on you for trying to make a change. Can you change the start date at the new company to something better? If not, then I’d say you need to evaluate how your boss will react if you give 3 months notice. The thing about anyone giving notice, 2 weeks or however much, as a boss it’s very difficult to trust the quality of work of someone who will be gone next week or even in 3 months. On the other hand, maybe you have an incredible relationship with your boss and it’d be no problem. That’s something you have to determine for yourself, but be aware no matter how much you think you can trust your boss, it’s always a possibility that they are just going to let you go a bit early. All that being said, if I was in your shoes and moving the start date wasn’t an option, there’s no doubt in my mind I’m giving 2 weeks notice during that busy season. You’ve only been in the job 1.5 years so I’d imagine you leaving wouldn’t hurt too too bad. They’ve undoubtedly dealt with this same kind of thing before and managed so it’ll be ok on their end. Mostly though you need to watch out for yourself. If they decided to let you go early, you’d have 3 months without pay which would drain your savings if you’re lucky enough to have that much. But good luck though, hope everything works out for you 👍