We all start off with the enzymes to digest lactose but since milk is baby food we mostly lose them by the age of about 4 - this does differ from one person to another and also by ethnicity.
Northern Scandinavians tend to retain a high level of lactose tolerance and use a lot of dairy...
Start with a tax-free account. You are allowed to put R36k per tax year into those. Perhaps, open an account with Easy Equities. If you're not happy with your first choice you can move into something different within the tax-free space. Just try to get that going before end of February.