I agree with Michael! I've been at it full time for nearly 10 years, and part time for 15 prior to that. The only way I am doing it full time is because of a military retirement check coming in, and a strict budget that depends only on that retirement and my Wife's income.
I can remember when I was part time, thinking how great it would be to be "one of the big boys" who gets to do this full time, and thinking those folks had it made. In reality, most of those "big boys" live a "hand to mouth" existence, and in some cases I have even heard them mention how they had to "take out a loan" to attend a show. I know that's likely not what you want to hear, but it is the truth.
If you have a good, steady job, with benefits and a retirement, my advice is to keep working that job, make knives on a part time basis, and then once you retire, you will be in a much better position to go at it full time.
That being said, everybody's situation is different, and if you have prepared, and have a sound plan established, you will have a better than average chance of success. Where our business differs from most is that our income is always dependent of others' disposable income. In "good times" we thrive, and when times are "bad" we struggle.
As to "how to convince her".....if she needs convincing, then it's likely a loosing battle to begin with.