your plant is really small there ,i have never seen PM in a small plant or in veg ,i have only myself experienced PM in flower when buds have weeks left to go .
as above says neem oil is a good prevention for your young plants in veg ,when there bigger spray a few times as instructed on label lights out with warm water a couple of times ,this should help prevent you getting it later on .
as in another post ,i would recommend buying a dehumidifier for your room ,they are bit expensive but will prevent mould & PM .I have never had both since .