Sorry in advance for the lengthy post!! But I really appreciate anyone's help

Twenty-three and not many dollars to my (or my fiancés) name, but after four years of dating, we're ready to take the plunge! Unfortunately, because of my age my mom is pretty against the timing of this. And that it would be at City Hall, unlike her brother's kids (and all her friends' kids), who all had traditional weddings. Though she hasn't said anything about being embarrassed, I know she would be ashamed or something similar. I can't put all the blame on her for that, because she grew up in a situation where she and her siblings were, from what it seems to me, in a competition. And her brother was generally the one put up on a pedestal. While she, even though she pretty much took on the mother role from an early age, stayed below him her whole life. And now that he's living in a nice house with his wife, with three successful children all married in the "normal" way--you're looking at the white-fence neighbor here. Talk about the golden statue idea from the Bible! Sadly, my father left my mom, so she went from a house with my three siblings and I, to moving us in with her mom and taking a minimum wage job. Now I can't even give her a normal wedding, and I feel really guilty about that. I feel like she can't catch a break, and I'm just adding to it and making her miserable and embarrassed. I wish I had the money to do something special, even with the city hall--whether it's a nice reception or maybe a nice ceremony and some drinks at the house. But we just don't have the money (and I'm not going to point out, despite her traditional mindset, that the brides FAMILY is actually supposed to pay for a lot of things. So since she's not offering, and I'm not asking because neither my FI or I want her to pay, it's really kind of irritating to have the issue of a non-traditional wedding put into scrutiny and disapproval.
I almost lost my fiancé because of all this, though. Cowardly complying with every and all family wishes for four years was too much, and he started wondering if a marriage could even work if I wasn't going to ever stand by his side. As he said multiple times, it's impossible to make everyone happy. If you try, you usually end up hurting more people (especially yourself). And he was usually the one getting hurt, and then having to pick up the messes and deal with any negative results thrown his way.
The thing is, I really want this. I know we can make things work financially. It's so incredibly painful to go through this with my family, though. I can't tell him "let's wait" or anything because that would be doing exactly what I've been doing the entire relationship. I don't need to wait; I'm just too scared of dealing with my family. And saying "let's wait...because my family blah blah blah.." would end things, no doubt about it. Can anyone help me? My friends have told me to: 'just pluck up Dutch courage and adopt an F-you attitude because it's my choice, not anyone else's. Just because my family wants me to follow one route in life, doesn't mean I'm required too or should feel obligated to. It may not be a bad or wrong route, but if it's not the one I want to go down, no one should make me feel this way about choosing a different path.' I know they're right, but I'm really scared I'll buckle under the pressure and retreat back into doing what everyone wants/tells me to do. I want this so badly, I just can't lose it. It's not an option.
I'm just scared, and I wondered if anyone could give me some advice for staying strong. I don't want to be this kind of person; someone too afraid to go after what they want because it isn't "normal" and people disagree with it. I hate that! I can't believe I got to be like this. Of course, if anyone has ideas for making our wedding special (and affordable) PLEASE send me ideas!

Despite everything, I'm pretty excited and want it to be as great as possible!

P.S. -- her preference would be for me to spend a couple years getting to know myself (going abroad and whatnot), starting a career, living on my own for awhile, and then going into marriage. Nothing wrong with it; it sounds nice. And because I was raised that way, obviously, it feels safe and "good." But I'm tired of hearing how she's "not telling me what to do, just trying to give me direction for how to make the best decision." I'm tired of hearing things like "I'm not saying I'm right, no one knows if they're right..." It's so aggravating; she means it but it doesn't seem like she really thinks it. I don't think she gets that even though her idea isn't wrong or a bad idea, doesn't mean that doing something else isn't okay or is less "right."