Immigrant or international student

Hello everyone
i’m currently in year 13 and have already applied to go to uni to study a nursing and midwifery course However I am not a British citizen but a Nigerian citizen but I have lived in the UK for majority of my life since I was four I’m currently on a dependent Visa and was wondering whether or not I would have to extend or change my Visa to gain legibility for student finance and other things I may need to support me On my course. The reason I’m asking this question is because one of the universities that I applied to recently sent me an email talking about tier four visas,However this was for international students and I am not an international student but an immigrant. I was wondering then if I would be treated the same as an international student coming from another country or as an immigrant because the tier four Visa suggest that you are a foreign student and you’re coming to study in the UK however I have because I have been in the UK for majority of my life I was wondering whether this teir four Visa is applicable for meOr whether I would have to change my dependency Visa to this tier four Visa.Because although I am not a British citizen I have lived in the UK for the majority of my life and therefore it would be unfair to treat me as a foreign student. Has anyone been in a similar position to me or know somebody that has been or knows what to do in this given situation and who I may need to contact such as student finance or the home office et cetera. Thanks for your help