As others have said, asking to be put on a later course is always risky as there is usually only a set number of trainees on each course which is carefully planned, also taking into consideration specific depots, routes and traction training etc.
Whilst I might not know your individual circumstances, if you’re worried that you have a lot on your plate right now in your personal life and you’re worried that you might struggle to juggle the course on top of that too, I am aware of multiple TOC’s (including my own) who are having to send trainees home for approximately 6-12 months after the classroom training before practical training due to shortage of trainers and backlog of practical training caused by the pandemic.
Whilst this may not be the case for all TOC’s, and whilst this may not actually help your individual situation, if you were thinking of delaying your course, another potential solution may be to work extremely hard and get the classroom training done, then use the potential time at home before practical training starts to sort out any issues you are facing.
If you are able to contact someone at your TOC’s training academy, hopefully they can tell you how long the gap is between classroom and practical training.
Feel free to send me a direct message if you like