I started mine when I had about 110hrs total time.
This worked well for me, and the IMC training and test were straightforward. The ground examination was very straightforward.
As others have said, on frequent occasions, the point is not so much to gain the rating, but to make every effort to keep it current. If that currency cannot be maintained, then have refresher instruction before using it in real IMC. Don't assume that the presence of the rating signifier in your licence immediately makes it possible or advisable to plan for sustained flight under IFR in IMC. There is a need to learn management of the aircraft itself, management of the real-time, non-flying tasks (e.g. communcation, navigational fresight, etc.), and management of yourself before being able to consider yourself safe. These matters can only be learnt by experience, gradually: though the learning of them can be, and should be, planned and thought through. The legal thresholds for currency are minima: real, practical currency requires IMHO more than those minima.
Again, as has been said, but it is worth reinforcing, to be able to fly accurately in VFR is very advisable before starting an IMCR or IR course. Also use of appropriate CBT aids, for example, RANT, is extremely helpful in complementing practical training in the air.