If her parents want to take some time, this means that they are not sure about you and might also be looking for more options meanwhile.
No parents (especially girl's) want to delay their children' s wedding.
What you need to do is give them a sense of assurance that you can take care of their daughter, provide and care for her. Once they see you're worthy of their daughter, they'll rush the whole thing more than you.
I myself was going through the same phase 1 momth back, we both told our parents on day 0, day 7 i was meeting her family (they were 80% satisfied), day 14 her family visited mine (100% satisfied), day 15 we had our roka ceremony.
It all comes down to how assured they are of you and how well can you convey this to each other's parents.
Hope this helps.