How do I get my mom's voice out of my head?

Hi,

I've just come to realize that without even talking to my mom, her voice is in my head and it's stressing me out.

Here's what's going on. I'm 25, I recently went back to school to do a certificate in translation and I am applying to grad school. I want to do my degree abroad for the best program and also the best experience on my résumé, not to mention life experience. However, financially, it's daunting. I have been working full-time and going to school full-time since September. I've changed my mind a few times about what I really want to do next year but about a month ago, I decided that I wanted to pursue a master's degree abroad. I've been ultra busy with school and work. I've performed really well in school this year, I take care of myself and eat very healthy food, during a really emotionally difficult period, I went for counseling, so I'm really good about looking after my well being. What I'm not so good at is managing my finances. I feel like I'm constantly screwing up financially, and I can just hear my mom's voice inside my head nagging me about my finances, and it just makes me feel even more overwhelmed. I was just looking at scholarships today and realized that a couple of deadlines had already gone by, and I can just imagine how irresponsible my mom would think I am right now.
I have a car that I bought two years ago when I had a job that I needed it for and now that I'm planning on going abroad, I have to sell it, and it's going to cost me a lot of money to pay off the loan. I most likely will get a good scholarship to the grad school I applied to close to home, but the experience would not be as enriching. I would most likely incur a lot of debt studying abroad, but I feel it would be worth it. But I constantly have my mom's voice inside my head thinking that I am an extremely irresponsible adult for not taking the scholarship at the university close to home. I'm 25 years old and I really don't even need to tell my mom any of this, so why is her nagging voice still adding to my financial stress? Sometimes I feel like I'm trying my best and yet I still keep screwing up supremely with my money, and without even telling my mom about it, I still continue to beat myself up with her voice, even though she probably wouldn't give me that much crap anyways.

Sorry for the length of the message. I just felt the need to vent before I go to bed. I'm a bit overwhelmed. Anyone know what I need to do to get my mom's voice out of my head and just decide for myself without fear of what my mom will think?