How much can make up de-age an actor?

I was planning directing my first feature film this year, but people are talking me out it , saying that I am not ready yet, and that I am getting way too ahead of myself, and that it will end up being a waste of money. I thought maybe they are right, since it's good to have outside input, rather than go by my own passion and judgment only.

I and another actor were planning on both starring it as well as me directing with another co-director hopefully, if I could get one...

However, I and the other actor are getting old for the roles in the script, and if I take a few years off to practice, we will definitely be too old for the parts then I think, which are meant for younger characters. If I take a few years off to practice more, we could still do it in a few years but we would look kind of old by then. We're already about five years too old for the parts already perhaps, and if we take a few years, then it will be about 10 years too old. I was wondering if make up could make us look ten years younger.

I am going to maybe say no, because for example, when you watch James Bond people complain about Roger Moore being to old to do A View to a Kill when he was 58. But if make up can de-age then why not just make him look 48? But the movies chose to age him as he went along, so I assume that maybe make up is almost useless when it comes to that?