12 months is a perfectly reasonable aim for a course. Many will find it takes a little longer, but many others could complete in that time.
Mine took almost 15 months, but I was flying the CPL over the worst part of the winter which added about a month and was ill and unable to fly for 6 weeks (also requiring some extra training due to lack of continuity). I also did not push the flying being in no great hurry and wanting first-time passes, so only flew once a day to allow plenty of ground study.
This was a modular course with more time taken in groundschool than strictly required.