I don't think training at late twenties / early 30s is that uncommon. Reason being that it is only usually at that age when most people have gathered the sufficient funds. Regarding distance learning ATPL ground school, it is very do-able but does require commitment.
I would completely agree with that. At my DL school I've been pleasantly surprised by the mix of ages of ATPL exam candidates. I had expected to be one of the oldest at 29, but many are in their 30s and some even in their 40s/50s.
I think it's a combination of getting the funds together, getting a bit cynical about your current career and realising that if flying is what you want to do you need to act, rather than just dreaming about doing it in the future and putting it off.