I think this is a great idea. However, schools might (and probably will) require you to send in all previous transcripts. I would recommend contacting the schools you are interested in and asking how they rank applicants and what you could do to make yourself competitive.
Many RN programs are highly competitive, so it might make sense for you to start with an LVN/LPN program. Again, do some research on the schools and see what their admission rate is.
Also, I hate to say this, but I would recommend some hard soul-searching on this one. You attribute your lack of success to a difficulty maintaining motivation. While I do sympathize with you (truly!), you may want to consider if you will be able to maintain a sufficient level of motivation throughout nursing school. Nursing school is very challenging and you want to set yourself up for success.
Make sure nursing is something you really want to do. I personally know people who thought they were passionate about the profession and worked their way to and even through nursing school only to find they did not really want to be nurses. The LPN/LVN program might also make more sense for you because it is less of a commitment than nursing school - though it is still quite a big one! - and you can "test the waters" of the profession.
I wish you the best of luck with your decision and whatever career path you choose!