Honestly, there's so many variables, including the fact that there's no guarantee in this market that, even after becoming an attorney, you'll make more money, that we'd need to know more about your situation to even begin to analyze it.
The variables would include your age, current salary, expected salary/area of law, how likely that is to get, promotion potential at current job/as lawyer, etc. Sorry I can't be more specific.
One way I've heard to look at is that you're losing your last year of work, which generally is among workers' highest-paid, so each year can make a difference.