Relationship Advice! Help?! 23 year old male problems

I need help with my relationship. I have been with my gf for almost 5 years (im 23 and she is 21) and she wants to get married/engaged. I just graduated from university and she still has another year. I want to make some money and I want both of us to have steady jobs before we get married/engaged.

She sees her friends and acquaintances from high school and college getting engaged and gets really jealous and upset saying things like "i'll never get engaged/married" and "i'll be waiting for you forever to propose."

WTF? we just graduated from college lol.

It doesnt help that her mother and family are being bitches about it and are telling her that I am stringing her along and ill dump her. They have also tried to convince her that I probably have cheated on her because they have all been cheated on before. (obvioulsy a lie, I would not do that)

I feel really bad because she is really insecure about herself and I encourage her all of the time to do other things but it seems like I am the only thing she wants to focus on I am the center of her universe.

The problem is I really love this girl because she is such a nice girl and smart and fun to be with. She is also my first real serious gf. ( she dated a guy in high school seriously for about 1.5 years and he cheated on her).

She also gets really jealous about a lot of things and I communicate with her all of her problems but all she does is cry really hard and I feel terrible for her and pity her. I do really care about her alot, its just she does a couple of things that bother me and when we fight about it she says she'll work on it or stop, but it will happen the next month or 2 months (conveniently on her period) lol. We also fight when I want to be left alone and she thinks I hate spending time with her.

I just need some different points of views on this. I know some will say I should communicate with her more but I have tried everything from threatening to break up with her to being kind and listening to everything. I wouldn't "waste" almost 5 years of my life on someone I did not care about and love but it seems I have a hard time getting that point across to my gf.

I know I rambled but thank you in advance for any advice!