Hi Ellie,
I have a start date in three weeks. I'm going through Aotearoa Diabetes Collective and paying for the training so I don't have to wait for that and the pump of course is free. I think my carb counting is pretty good and my ratio seems right. I was over insulin bolusing for quite some time but seem to have resolved some of that. Im excited about the pump as I lead a very active life ( or at least I did) and I think this will return the possibility of that. Keen to go surfing again.
Tandem isn't waterproof so when I do water activities I detach mine and reattach every couple of hours to give a dose of insulin. Also, cgms tend not to work well in the water (bluetooth connection) so you'll need to watch out for hypos. Not trying to put you off surfing but you need to be aware of the tech limitations. I'd hope that a newish diabetic would have good hypo awareness so it shouldn't be too much of an issue. Certainly when I was on my tandem intro course there were some very active people attending. There are also plenty of exercise threads from the T1s here so I'd hope you'd find the forum useful.
Be aware that insulin ratios can change (illness, weather, activity, age, etc, etc, etc) so you'll probably have multiple insulin profiles on your pump and you're likely to need to adjust them (specially if you're in honeymoon period).
My tandem isn't perfect (my main gripe is that there is no way to tell it that my insulin resistance goes up when I'm over 10 mmol/L so I have to manually correct then) but I love it compared to MDI (I truly hate lantus). Also, if you are controlling things via very low carb my dietician was adament that I should have at least 30g per meal for the tandem. I don't but I admit that things are easier when I have at least 10g for breakfast, as the dawn phenomena gives me a ridiculously high insulin to carb ratio if I don't.
Of course, I'm a long term (more than 50 years) T1 so not producing any insulin, so your circumstances may be very different.
But in conclusion, I love my tandem.