They are vastly different not a little bit different and you can brush it off now. A teenager is woefully inexperienced. An early 20th person is marginally inexperienced and generally an adult. That's why they're seen differently and are not comparable at all to adult relationships. The seven year difference in the characters is wide enough that it's questionable. Raising the pitchforks I wouldn't say but definitely questionable, one in which people should step lightly with friends and family close by. This being said with the younger one being so young, there's no guarantee of any longevity just hope of a positive beginning and end.