<human>: Can you provide a brief overview of the text?

I've known my friend literally for as long as I can remember. We grew up together and both consider the other as best friend.

My friend has been single for a long time, with no relationship after high school that lasted more than a couple of months.

He has also had some issues with sexuality due to his upbringing, and has only recently lost his virginity (to his current gf).

The two of them have been dating for about 3 months, and he called me last night asking me to be his best man in summer of 2014.

He said that a couple of weeks ago they were talking and she said her previous "loser boyfriend" (my friend's words) had proposed to her a couple of times, which she declined. My friend asked her "If I asked you, would you say yes?" She replied that she would.

He now has purchased a ring - which she picked out - and is waiting for it to be delivered. He will pop the question when it arrives in a few weeks.

I want to meet with him as soon as possible and tell him that I think he's rushing in far too quickly (especially since I've only met her once and I'm to be the Best Man at the wedding).

How do I tactfully go about this? What should or shouldn't I say or ask?
<bot>: My friend is about to propose to his girlfriend of 3 months, after having been single for years and losing his virginity to this girl. How do I tell him he's moving too fast?