Moving out on my own and needing advice ?

Hey everyone, I need some advice about a situation that I am dealing with. Recently, I have been working on myself and working on a plan to improve my situation. One of the things that I am focusing on is the opportunity I have for a new career and for the ability to be out on my own and have a place of my own and have my own car. I will be making enough money to have my own place in our area(grossing around $2800/$2900 after taxes per month; rent is around $800 - $1000) and my plan for a car will be to save my checks while I can(right now I am currently living with family) to buy a car outright to avoid having to pay a car payment every month as I do not want to take more out of my check than I care too.

I also checked out 2 places to live a few weeks ago and one of the places I am really fond of due to location(grocery stores, pharmacies,etc.) and it being near the bus line in case I have the option to use public transit if need be. It may not be the best area but it will allow me to have a place that is my own. Overall, I am looking forward to my future and getting back on track to where I need to be. I also plan to figure out schooling as well as I want to go back to school and finish my degree but I know I will have to figure out my scheduling as I will be working a full time position. But I want to be able to prove to myself that I can do anything I put my mind to.

Now some of you may be asking "Well, whats the issue ?"

Well, lately I have had one person(considered them a friend) seriously discouraging me from doing this.

Now I have known them for years, and around the time that I was down mentally, they did help me as being supportive in my time of need. But now, as I progress and make plans to do the things I want to do and need to do, they have been undermining me with condescending statements and comments that have a negative undertone. The comments often consist of "Are you sure you want to do this ?" , "You have never been good at making decisions" or "Well I don't think you are responsible enough to handle being on your own" or " What if you crash and burn ?". This person still lives at home and has no plans to move out any time soon and hasn't moved out at any point and they are in their late 30s(I am several years younger than them). The comments got so bad that I slowly began to question the idea of this and whether or not I will be able to do it.

Does my plan sound realistic ? Is there anything I can do to help prepare myself for life on my own ? Is there any frugal advice for those who are just moving out on their own ? How do I prepare myself the changes I know I will need to make in order to have a successful move?