I am sorry for this delayed reply to your gardening question. The spring rush has brought a deluge of questions and we are working hard to catch up!
I know of no way to speed up maturity of an avocado seedling. The time to fruiting will vary a lot depending on growing conditions and seedling genetics. Most seedlings will not be that similar to the parent fruit, thus grafting the seedling trees is recommended.
The following web site will offer a lot of good info on growing avocado trees:
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
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