I've never heard of someone having a policy of not breeding until 2 years old. Either his gilts are small and very slow growing, or the boar is huge! As others say, it depends on how well-grown the gilt is - and it's really important to match her size to that of the boar.
Mine are normally ready at eight months, so their first service is between then and 10 months old. I did have one which was caught by a (thankfully unrelated) young boar at six months old. She had a lovely litter of eight, and has just had her second, which was 11 live, one stillborn.
Good luck with everything,
Liz