Look for lines alone the bottom of the teeth. This could indicate areas where the gums have receded. Also look to see if areas of the teeth have worn away. Do your teeth look much longer than normal? This could be a sign of a receding gum line. The gums could have pulled back from the teeth over time.
There are other signs that you have a receding gum line:
There is an awkwardness when you bite down.
You experience bleeding or sensitivity when brushing or flossing.
Your teeth are loose or hurt when biting.
If you can see more of your teeth than you should I duno
Ummm I think a dentist wud have to tell u for sure