The answer is: Grandmother is adept at several types of art: painting, sculpting, and engraving.
The above is the correct sentence since it uses a colon properly by placing it before a list (it could also be an enumeration or an explanation) to be immediately developed after it. Also, after a colon, no capital letter should follow, unless it is a proper name or an acronym.
Finally, when presenting a list, the proper way to do it is to separate each element by a comma, not a semi-colon