Since it's a new boat, it has a warranty. I'd let the dealer do the service
while the warranty is in effect.
My dealer checked everything at 20 hours: their 100 hour/annual service
checklist is two pages long, including alignment.
You should have an Owner's Handbook - mine is generic for several models -
that lists recommended services and intervals.
Oil, filters, lubricants are cheap insurance. Don't forget to check you
wheel bearings, too.

"Genius? Not!" wrote in message
. ..
I'm taking my new boat in for a 20 hour service.
Should I have them change the fluids while they have it or should I change
the fluids later per the manual?
How often do you change fluids?
Anything I should pay attention to at 20 hours?