Winning 400 metres freestyle silver behind Katie Ledecky ranks as good as gold given the gulf between the U.S. teenager and the rest, and Carlin certainly felt she had given it her best shot.
Speaking to reporters in the early hours after Sunday's late night programme timed for U.S. television audiences, Carlin reflected on the race of her life and also a far greater distance travelled.
''Four years ago I was sat in the stand cheering Team GB on but now I'm actually part of the team and to come away with a silver medal is absolutely amazing,'' said the 25-year-old.
''I have been to worlds, Europeans, Commonwealths but it's everybody's dream to compete at the Olympic Games. I am absolutely elated.''
In 2011, Carlin came down with glandular fever and tonsillitis that knocked her sideways.
The Welsh swimmer, whose close-knit family life had already been rocked by father Roger suffering two strokes over the previous 10 years, failed to qualify for the Games she had dreamed of competing in.
Instead, she did some television commentary and considered her future.
''I went on holiday directly after the Olympic trials just to get away with my family and didn’t even look at a pool, whereas normally I'm like 'can't get me out','' she recalled, after qualifying for Rio, of that dark period in her life.
''It was tough. I had to take a few months out to reassess but I thought I'm just going to give it one more shot and obviously I didn't have any major expectations.''
Carlin came back for the 2013 world championships and finished fourth in the 400. Normally the worst place to be, she took it as a stepping stone back on the path to success.
The Briton, who at home sleeps in an altitude tent that simulates the oxygen levels found at a height of around 3,500m, won the 800m free at the 2014 Commonwealth Games and took bronze at last year's world championships in Kazan.
''Missing out on London and being so close...that really did knock my confidence and it's now that I'm starting to build it back up with the Commonwealth Games and Europeans,'' she told reporters before coming out to Rio.
''There will always be voices in your head -- 'Am I good enough? can I do this?' -- but yeah, I'm starting to finally believe that I can do it.''
(Reporting by Alan Baldwin, editing by Neil Robinson)
