Is it okay to get a dental implant at the age of 18?

I turned 18 in October of last year and in my most recent dental consultation, a dental surgeon suggested I wait until I'm 20 or 21 before I get a dental implant. The two consultations prior to my last one both said I was a qualified candidate for a dental implant, but neither spoke as detailed as the last dental surgeon who specified the reasons as to why I should wait. He did not take a CT scan and said that he could tell I was still growing and advised against a dental implant at this age. However, from many sources online, 18 years is the minimum age to get a dental implant for males. Also, considering that the first two consultations (which occurred within the past 2 years) determined my qualified candidacy and that, according to online sources, further delay can decrease the available bone above the area of my missing tooth (which could lead to the need of a bone graft), should I still push for a dental implant?