Are marriages designed with women in mind?

My mother got married at 20. It was an arranged marriage between her family and my father's family.
They've been married for 21 years and are happy with each other.
I am 20 years old Right now.
And there is someone currently asking for my hand in marriage. He has made promises and has told my family about his plans for my life.  Objectively speaking, they are good plans. But I don't want them. My parents are on board with the idea. They are delighted even. It is such a good opportunity for me and failure to see it is seen as wasting it away.
There is just one problem. Me.
I'm 20 years old. He's 34. Which is too much for me and its not fair to me at all.  When he was 20, what was he doing? Was the prospect of marriage on his radar? Why does he want to rob me off of this period of ny life that is supposed to be for me. This period when I'm supposed to go out and do my thing? Why doesn't he go for someone his age? Why is it a good idea for him to come on to me and it's applauded.
I just graduated from university and I'm currently undergoing the  mandatory one year service for youth in Nigeria The Nigerian Youth Service Corps (NYSC). And I'm being paid for this period which is a good thing. Before the marriage proposal,  I was supposed to finish my Service year and go for my masters which my parents would have paid at least part for me. Now, with the new development and the promise of paying for my masters if I allow him, my parents have told me that if I don't marry him, they won't pay for it because I saw an opportunity and wasted it. So I should be able take care of myself since I now have the ability to make decisions.
I have a degree in Policy and strategic studies from one of the prestigious schools in Nigeria. Covenant University.
But I can't sponsor myself for masters. For now. I need a job that will enable me to save up at least. 
I can't believe that this is a problem that I am facing at this moment in my life.
And I'm trying to explain to my parents how this is not a good idea and I'm referred to my parents marriage.
Their families saw they were ready for marriage and they were brought together by the families. And their marriage has been fine. But I've been more exposed. I am not against arranged marriage. But people, women especially should not be forced into marriage. At any age. There should be room for her to say 'I don't want this', and it stands and people respects her decision.
Also women shouldn't be threatened into marriage. If I go into this marriage because of what he has promised me and he fails  what next? My life has just been sent down an unknown path that I may not even be happy with the results.
And say he actually funds my master's degree. That degree will never be fully mine. There will be a part of it that will always be his.
And it's not a good idea for me to go into marriage with nothing. Fully dependent on my husband.
I should be a better person than I currently am. In all areas of my life.
I shouldn't have to depend on him I should enter marriage with something that is mine. That I have done.

And I can't help but feel like an arrangement frmarriage where one of the intended spouses vehemently refuses is not off to a very good start. And if the tables were turned, if he didn't want to d anything with me after being introduced to the prospect of marrying me, this would not be an issue. At least for him. 

Why is it like that? Why is my opinion looked down upon but his is respected and applauded. Why am I not allowed to speak up for issues that directly affects me and shape the course of my entire life. Why can't I say no to this marriage without fear of what my family might do to me if it happens. 
But my parents don't understand this. And I don't know how to go about my life.
It's not an issue to say no to the marriage,  but I want to go for masters primarily. And I gave no means of actually going about it. And I would like to know what the next step to take in direction of getting a masters without my parents funding.