There is nothing wrong with spending 120k on ones first plane. I spent nearly 2x that 9 years ago and never regretted it. At the time i had a PPL and IMC only.
The real problem is that ownership in this game is not like a Merc etc. It is a big learning curve and for various reasons to do with the way this business is structured (putting it very politely) there are many pitfalls for the unwary. There is no such thing as a trouble free aircraft especially a Diamond which give constant trouble to schools who operate them. My TB20 is more or less such (which is why i am typing this on the beach at LGKC, on that horrid piece of crap called an Ipad so sorry for the grammar) but that comes at a heavy expenditure in time and micromanagent of everything down to not sending the magneto to a certain uk shyster for an overhaul and sending it to the USA instead...