When should I tell her I'm rich?

Okay, so I'm about to go on a date with a girl I just met. I know she is going to ask me at some point: "what do you do?" The truth is, I do a little studying at my local university and I do volunteer work. Now, I don't have an actual job because I'm wealthy (trust fund baby). I'm afraid that when she hears this she will think I'm a bum with no direction in life. I don't think this would be shallow on her part, it's a reasonable judgment to make, I mean we are in our early-mid twenties, normal people should have jobs. I almost feel like just saying "I don't work, but it's because I'm rich, not because I'm lazy or can't get a job." But, I don't want to say this because I hate flaunting my wealth, I dress and live modestly for this reason. I just feel like no matter what, I'm going to come off as a bum, a sleaze, or a liar.