First and formost, you have to realize that your mother has your best interst at heart. If she was a worthless mother who didn't care about you, she would let you do as you please and as far as the teasing goes, that's part of showing you that she cares too. Asking questions shows she wants to know what is going on in your life, and not to just be nosy, she is I'm sure, concerned about the friends you have, are they a good influence on you, or are they going to get you into trouble? She is concerned about your life and your future. She's probably proud of you too. So don't be too upset with her, ok?
If you have someone you want to date, not because you feel bad for somebody but because you really want to hang out with somebody, then you probably are headed out to a date anyway. My point is that when you are ready to date, your first date should not be about you going on a date when you do not really want to; it should not be because you feel bad for somebody and you want to cheer him up - that's like creating false hope for somebody and you do not really want that kind of attention if you do not feel the same way as he does because some day you will want to hang out with somebody else that you really have feelings for and you will have to break up with whoever you are dating because of your 'sympathy'. It's pretty much the same when you choose your career because of what you want to do rather than because of what people tell you to do - when you have no interest in doing what you are doing, your heart and your expression simply would not show because what comes from within simply has a whole different way of expressing itself.The way you think your folks would respond is simply built into your culture. Your description is the image of how you think they will respond but, in reality, even if it does turn out to be the case, they are simply fitting in with the social norms so you should not feel too embarassed (although that is a part of the social norm too). You can just play it cool because you know you can expect it and have to deal with it at some point of time, and better sooner than later, right?If you are worried about your friends talking about you having a boyfriend to your folks, then perhaps you should do the talking before they do - that way, you are not keeping them in the dark about your date and it would not come to them as a shock when somebody else mentions it.