I don't have a great voice but I love singing and think I can better. Is 16 too late?
It is not too late to start voice lessions. Actually, now is a perfect time to start voice lessons. Your voice is now developing, and at 16, your voice is better developed to be trained.
Your voice will not actually stop developing until your early 30's, and if you are going to be doing opera, there are some pieces that you may not sing healthy until your early 30's, due to training and vocal endurance.
If you are doing opera, some voice teachers will want you to learn songs that are FAR beyond your ability. You may not know that you're really damaging your vocal cords until it's far too late. So feel free to ask "Is this song okay for me to practice at this age and time in training? Will it hurt my voice?"
Example? You know Mariah Carey? Those high notes she hit when she was younger were not healthy by any means. If she were to practice them and use more classical training, she would still have those high notes that she was famous for. Her manager pushed her too much.
Do not let people push you around with your voice. If you become a full-on singer, your voice is your career, don't let anyone push you into anything you are not comfortable with, or may be vocally unhealthy (or physically for that matter).