You will be totally fine if you enter the TW.
I did it this year with no training and never having done any seriously long rides. Granted I was at the back of the pack every day but all the same it was doable…
I had a good time, meet some nice folk and generally had a laugh. Some days were hard going though and you need to be prepared to just grind away for hours on end, sometimes on your own!
Mixture of bikes-a short travel full suss is probably the most popular choice and probably the best one for most folk nut there were HT’s, 29ers, 29er FS and SS riders too!