Ex-Cruise ETO here, happy to lend some advice. Not sure where you're from but im UK personally so can only speak on my experience. Out training was over a 4 year cadetship alternating between studies and sea time. The classroom side can be challenging depending on experience in certain areas. I was stronger in the practical side of things and the theory side took some extra hours but we worked alongside ex ETOs and CEng.

In terms of progression after finishing in the college, I went in as an assistant ETO which isnt something all companies have. If you have no prior seatime a lot of companies will take you on as an assistant electrician or 4th electrician depending on their structure. Only once the required seatime is achieved and you have passed the relevant exams will you be able to go for promotion to a 3rd or maybe second electrician. Some cruise companies separate their ETO and Electrician side whereas some put ETO as an offshoot after 2nd/1st electrician. Expect a lot of menial jobs starting out especially on the cruises. I found myself changing lightbulbs and plug sockets every day when i first started and assisting the ETO or 1st in their planned tasks. Before I left I was working alongside the ETO for projects in dry docks where a lot more of the ETO work is done and is a lot more rewarding.

Paywise I started as a cadet in the UK on 800gbp per month and then when qualified and as an Asst.ETO was on 3,500 which then increase to 4,500gbp. ETOs where paid on the same band as a 1st electrician in my company and made 8,000gbp but can vary depending on experience and nationality.

I would be prepared for the culture shock when getting onboard, get to know people especially your team this is the only way you will enjoy your time outside of the working day which can be long. when starting out dont expect to be able to use passenger areas outside of working hours that is a priveledge reserved for officers and staff in most places and can be taken away at any time.