Start checking the job market now, this will give you an idea what jobs will be available for you when you graduate.
As for the language, if you want to live in The Netherlands you will have to learn Dutch eventually. That most people speak Dutch means that it's easy to get by as an English speaker, as a tourist and for the basics, but it's different when you actually live in a country and don't speak the official language.
I know this as a language teacher and from expats living in my home country, Denmark, where the English proficiency is also very high. Maybe your car mechanic doesn't speak English, maybe you'll get some documents in Dutch only, maybe your bank advisor/doctor/lawyer/accountant/real estate agent etc. does speak English, but not at the level needed for important, in-depth communication. Not to mention, you will be at a disadvantage in the job market, you won't be able to integrate fully, and people will, after a while, expect you to start speaking Dutch. Remember that even though people speak English, they are still doing you a favour by switching to English in your presence, and with some people, they might speak English, but they might not be comfortable doing so.
So like Butterflywings says, if you want to live in The Netherlands, start learning Dutch now. It will be a huge advantage.