.
Depending on your age, you may have come under the Sexual Offences Act 1957 now of blessed memory,
and there is a statutory defence (or there was ...) that if you the fella is under 24 and the girl over 15 (which you will notice is the case you describe) then you could plead that you didnt know (she was under the age of consent)
This defence meant you automatically pleaded guilty to indecent assault. oops
Indecent assault (1957 and prior) has now been replaced by the 2004 Act and Sexual Assault. Same thing different tariff.
Under the 2004 Act you can 'do' it abroad and still get screwed in this country. [ yeah yeah I know big arguments about availability of witnesses and joosteece and so on ] .