There are lots of us who are doing the modular route with a full-time proper job - it's quite common. Part-time instructing is probably the way many people start; the problem is having an understanding employer who can let you have time off and, of course, there comes a point when you'll want to bite the bullet and become a full-time pilot.
However, do your costings and research well. There's a lot of sound advice on this forum and many questions have been asked before but you are certainly not the only one.
Cheers
Whirls