Take the first opportunity you are offered to go to sea, even for a short trip, to find out if you either get seasick or are scared of the sea. If you do then think of taking up bird watching or some other activity.
I know this sounds flipant but there is no point in investing a lot of time and money just to find out later on that you are not suitable. Don't worry about a little seasickness though - almost all of us end up looking for 'Hughy' one time or another. I have spent 40 years at sea (off and on) and still get seasick in bad weather. It is the chronic sufferer from seasickness who should stay ashore.
Incidentaly, you know that there are three degrees of seasickness:
1 - When you think you are going to die
2 - When you want to die
3 - When you realise you are not going to die.
Been there, done that and the t-shirt has since been washed [xx(]
Anyway - good luck with you aspirations // Skipper, Yachtr Nausikaa