sometimes right away is best!
She might be waiting for you to ask her out.
The longer you wait, the more likely she is to have other experiences that will take her on a road away from you.
Then again,
The longer you wait, the more experiences with *you* she will be observing.
In the end, you want to find out if she will be your pal, so get to it!
It is better for both of you to find out how this will go, before you waste alot of your times thinking and not doing.
If your worried about rejection, ask quietly and privately, by note if you like. After all, you'll be dealing with this person whether the outcome is more intimate or not, and will want to be prepared for a healthy existence afterwards, regardless. Good luck guy.
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"I'm sorry Katya, my dear, but where we come from, your what's known as a pet; a not quite human novelty. It's why we brought you.... It's nothing to be ashamed of, my dear, but here you are and here you'll sit."