Achilles

In reading about the events leading up to the Trojan War, the Apple of Discord was 'tossed out' at the wedding of Peleus and Thetis, Achilles parents. Now if Achilles was born after this then how is it that he was a young adult and established warrior during the Trojan War which I assume happened shortly after this event? And how is it his adult son took revenge on Paris after Paris slew Achilles? That's a lot of time unaccounted for. I know the myths don't always follow logical timelines but I was wondering if I missed something or have misunderstood something when reading this particular account. Any clarification would be appreciated.