You won't be able to retrieve any data from it unless your PC recognises it, and since it doesn't recognise it, the only way to get data off it is by sending it to a data recovery specialist which costs a hefty amount of money.
As it's only 3 months old you need to contact Seagate for a free replacement under warranty.
You can try extracting the drive from the enclosure and putting it into a third-party one. It could work again if you do that because the bridge-chip PCB inside the Seagate enclosure may have failed. A new enclosure comes with a new bridge-chip PCB, so it might be worth a try, but doing that will invalidate the Seagate warranty.
So it comes down to which is most important to you, trying to rescue the data, or getting a replacement drive at no cost to you.