I've had some young sheng puerh that I enjoyed the same year as it was harvested, despite being bitter-phobic.
How long it takes for them to age to enjoyable depends on how you brew them and your taste preference. Very very short infusions can make even fairly aggressive young shengs delightful to me, in part because I enjoy my tea when it is quite dilute. The long and concentrated infusions preferred by those who want their tea to look like expresso will make such a powerful young sheng unbearably bitter.
So....one tea, two very different experiences of drinking it.
How do you like your tea?