Early thirties is nothing (I was quite a bit older than you when I started medical school). The 'previous degrees' thing is irrelevant - it's not uncommon for mature med school entries to have several previous degrees.
However...I'd be interested to know why you want to be a doctor. If you are harbouring any desire to 'help people', I'd say - nope. Don't even think about it. Interesting comment above too about being able to cope with the blood'n'guts aspect - yep, you'll be the one trying to site an NG tube as that patient vomits up their own shit. And then you'll go straight off for your lunch after as you might not get another chance to eat or drink all day.
Emotional aspects: have you dealt with people in extreme emotional states on a professional level before? Because many of your patients will be going through truly dreadful times, they will die horribly right in front of you, then you will have to go down and see them in the morgue. Others will lie and steal and threaten you/your colleagues. And then there's the relatives...
Money: the funding situation changes year-on-year. My understanding is that - right now - full tuition and maintenance loans are available to those studying medicine with prior degrees. But can you face graduating with colossal debt? You will find it very difficult to work p/t beyond the first couple of years. If you end up resitting exams as a result of needing to work as well as study, be aware that this will affect the 'points' that increase/decrease your likelihood of scoring your first job in a location that is not across the other side of the country. Medical school is hard no matter how smart you are, plenty of 'smart' students come unstuck.
The bottom rung of training is absolutely, truly bloody awful - I won't repeat the comments above that outline why. To that, add in the stress of working in what is now an essentially failing (and frequently unsafe) system. I expect you have read about the Bawa-Garba case? That could have so easily been any junior doctor in the country.
There is at least rather more flexibility around p/t working now due to an overall shortage of junior doctors. I know numerous p/t trainees at all levels, and I intend to continue my training p/t after this year.
I don't regret retraining - it's truly a privilege to be allowed to share in people's lives in this way, so many talented and hilarious colleagues, etc, etc - but it has not been what I expected and I realise that I will need to scale down my ambitions considerably for the sake of my physical/mental health.
Oof, that was long. In summary: absolutely possible, but you have no idea what you will be getting yourself into.