To be honest with you, I have own, bred, trained and sold a lot of horses, and as much as I adore horses and always will, selling them getting out of them, was the best thing I could have done. Financially I can now say I am doing VERY well
as I don't spend every penny I make into horses again AND it gives me a lot of free time to focus on family and other things that are important in my life.
HOWEVER you have to be honest with yourself. Are you selling her because of financial and time management reasons, or are you honestly thinking you are holding her back, and will be looking at a different horse?
If it's a financial and time reasons, it's perfectly fine to think along that line. Things in your life must have changed since you've bought her for you to re-think your current life-on the other hand if its a training "issue" I would definitely think about it some more. Horses don't think like us. They dont sit in the field thinking "oh I wish she would allow me to jump 4 foot fences, or I wish I could be doing 2nd level dressage". Horses are happy in a healthy, fulfilling environment with their owner. As long as her basic life needs are being given and provided, she will be very happy continuing at your current level of riding. Especially if staying in horses is what you want, if she is as talented as you say she is, I would definitely hold onto her. There are no problems with the 2 of you continuing to grow together as you become more experienced as a rider-a big mistake a lot of people make(one I have done myself).
Make yourself a list of the pros and cons-dont share it with anyone. Do YOURSELF that list and then decide what you want to do.
Good luck selling your first horse is never easy.