I think if you have most aspects of life set in order (good job/ good resume, friends, family), then quitting your job and taking out a loan would just help fuel your recovery financially in a good way. If you're life isn't perfect, but you made an active effort and your BEST effort and not just lazy effort to improve everything in life, I'd say you're still a good candidate for LL. Noticed a trend of software engineers in Silicon Valley quitting their job and doing LL and easily being able to recoup the loss. Unfortunately such a job is limited to only a percentage of the population and most people aren't as fortunate to be able to get such a high income job with easy re-employement at such a young age.
If height is really affecting you in such a way that you feel like you're not gonna change your neurosis anytime soon (talking, years), I would say take out a loan. If you're in your early to mid 20s, this is undoubtedly the best time to get LL, you recover much much better. Late 20s early 30s is also good. Once you start hitting late 30s, I would imagine you can never forgive yourself for waiting until you were that age, your prime years are long gone, and now you're still stuck with this height neurosis. Not much point in sufferring an extra 10 years for almost no reason and still being unsatisfied afterwards because you chose to not do LL.
The way I see it, loans can be repaid, youth can't. If you are truly upset about your height to the point where you feel like you can do so much more with a few extra inches, get the damn loan and worry after. If you're unemployeed or a NEET or hikikomori and you blame height and want to get LL, I guarantee you that you not be happy post-LL. Get your own life in order first, get a loan, and post-LL use your debt to fuel the fire in improving your income and paying it off.
Don't waste 10 years pondering whether to get LL or save money first, try therapy and if it's useless then get the loan and go forward with the surgery.
All you have to do is save enough money so that WITH a loan + your savings you will have enough money to go pay the surgery fees and housing for a year and a like 30k extra for potential complication surgeries. The second you hit this mark in savings, go for it.