I'm sure this beer improves with age, however, a 4 month secondary sounds like an oxidation night mare. I'd finish the beer to completion, then either package - or if you must - rack to a vessel that has been purged with co2 before any extended aging.
If you bottle, taste it as you age it. You need to be the determining factor on when the beer tastes like it is ready, not an arbitrary time line. It probably will taste great fresh and change as it ages, either for the good or the worse.