Pretty sure he's talking about pill-popping. I doubt having a cup or two of tea or coffee will not hurt you, but there are a lot of people who can't seem to handle the stress and do things they shouldn't do. That's when it becomes troublesome.
OP, you're not too old. There are just some things you need to do, like take the pre-req courses, take the MCAT, get some shadowing/volunteering/possible research experience, etc. to get everything together for your application.
You also need to make sure your family will understand and be able to deal with what will be happening in the coming years. You won't be working during medical school, so will the bills be paid without your salary? There's other questions like that, and if your family is supportive and things seem good from a logical standpoint, you should be fine.
I haven't read all the posts, so if I repeated some things, I'm sorry. But OP, good luck