Tried sending a personal welcome video before week one

I teach guitar online and most people who quit do it in the first two weeks, before anything clicks. Instinct says they leave because nobody talked to them yet, so I recorded a 40-second hello on my phone for each new member last month — nothing scripted, just their name and what we'd start on. Small sample, I know. Before I decide this is the fix, is it worth me splitting the group so half get the video and half get my usual email, or is that overkill for a one-man studio?