First, I believe the challenge of becoming a virtuoso at anything involving motor skills starting at a later age has as much to do with the physical body than anything else. When you start young your muscles, tendons and joints adapt, grow and strengthen with the activity you are engaging in.

The thing I do better than anything else is golf. I started at 10. By the time I was 20 the muscles used to move the golf club in the proper positions and with speed were well developed through my growing years. I have seen older people take up the game and watched them struggle because their bodies are less supple and less strong. While I have lost some distance as I age my "golfing" muscles are still strong and fast compared to younger people who are just getting started, but I am a better player than ever before primarily due to mental maturity. The fact that you started playing at 17 helps since you caught the tail end of your physically formative years and probably have fairly well developed "guitar" muscles, depending on how much you actually played.

Second, there is the time factor. If you started playing at 7 like Yngwie Malmsteen, by the time you were 20 you would have a massive amount of practice time under the belt, and your body would still be getting stronger. By the time he was your age he had 28 years of intense guitar playing experience.

Third, is the talent factor. Have you ever had "guitar" talent? Only you can answer that question. Without God given talent you will never rival the best.

All that being said, I believe you could get good enough to impress a lot of people...but rival the best?