not about injury but about doing rather than being as it relates to the Asana. Many times we rush toward goals or final poses only to discover we've missed some of the fruit, the nectar of being present in our practice.
I personally have no idea about the time frame for reaching Hanumanasana. It's irrelevant how long it takes. What's of prime importance is the mindfull nature of your practice, full hanumanasana or Tadasana for that matter.How long does it take to stand with proper alignment in tadasana? How long does it take to master Adho Mukha Vrksasana in the middle of the room? It matters not.
It's like students in Adho Mukha Svanasana with their heels to the floor (or not). The hamstrings may never fully release for them. And that's okay. The pose can be rich and full without the heels to the floor. And working the hamstrings may be a lifetime "sport"