HS,
As FFF says there is nothing from stopping you doing the training but no issue until 70hours PIC in that logbook.
The twin rating is good fun and all additional training makes you a better pilot, in fact it was the first add on I did once I had my PPL.
However if you don't have ready access to a twin, have you considered doing an IMC/Night rating. They are likely to give added skills which you can use more frequently.
FD