Just let the picture thing drop and don't mention it for awhile. However, if she mentions a webcam, just say that you won't even try to get one until she shares a photo. Fair is fair. Also, is she willing to put herself on a webcam for you? Unless you both are using one, I don't see why you should alone.
In the meantime, just enjoy writing and getting to know each other.
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No matter what your age, you don't need to change the world to find love, sometimes all that has to change is you. Be open to the possibilities.