in m humble opinion it is a good idea to learn drop thumbing, and frailing, AND FOUR FINGER PICKING right from outset.
by four finger picking i mean, an adaption of a guitar style, thunb covers 5 and 4 strings down, index covers 3 string, middle covers 2 string, ring covers 1 string, this gives a flowing mix of up and down picking, if you learn all three styles from outset, you will be comfortable, altering style during a song, if you want to