While it’s unusual for high school relationships to survive distance and growth (or even lack of distance and growth - growth is always a given), it does happen. And sometimes it doesn’t work out in the short term, but couples reconnect later in life and it does; I know of several instances of that happening.
A friend of mine once wisely said that successful relationships are based on three things: luck, timing, and a bit of magic. To that I would add maturity (but that often is tied into the timing factor). Meeting the right person at the wrong time can sometimes work itself out later in life (and I don’t necessarily believe that there is only one right person). The pitfalls come when you meet the wrong person at the right time.