Me and a couple of my friends seem to have the same problem with closing.

I am new to this and don't practice pua all that much but I have been reading a lot about inner game.

So, all goes well with me, get numbers, conversations etc, but when I ask if the women want me to walk them to their class/apartment /subway station, they almost always turn me down.

This has happened to my buddies as well.

The question then is, is this because it's too quick to ask to walk with someone.? Not enough rapport, etc?

What is the correct or preferred strategy to close a conversation?

I have also found that I tend to talk too much, although there always seems to be reciprocation... Could anyone comment if this is a good or a bad thing?

TL;DR game is OK, until I ask if they want to take a walk, what's wrong?