Can an adult tooth erupt at 31 years old?

I'm 31 and after suffering tooth pain on and off for a couple of years I was advised by my Dentist that my tooth was decayed and root canal treatment was not an option because a) the tooth in question did not have a lot of bone left on it and b) strangely I have another tooth underneath the problem tooth sitting hidden within the gum! It appeared on x-ray. My dentsist suggested that the tooth underneath may work its way and erupt now I have had the damaged tooth extracted. I am obviously no expert but I found that hard to believe as its been there 20 odd years? I guess no expert would be able to give an opinion without looking at the x-ray but to help give you a better idea the tooth was a no 2 pre molar (last one before 1st molar) and when the extraction took place my dentist said he could see the top of the tooth underneath. Right now its been almost a week since extraction and the gum is healing nicely but I am wondering if it is a possibility that it might make its way up and if so how long should I leave it before I make a decision around having it surgically removed so I can start the implant process?? Really love to hear opinions.