Since the Paris Marathon is the first weekend in April, youve got 11 more weeks of training left. Assuming you do your last long run 3 weeks before the race, that leaves 8 weeks to build up from running 9 miles to 20 miles continuously, the longest training run done by most marathon first-timers.
Since the build-up will exceed the 10% rule of thumb for safely increasing mileage each week (supporting runs and long runs), theres greater risk of injury. You may be able to achieve your goal as some people can handle more stress than others, but Id advise choosing a later race to allow yourself enough time to properly train for a marathon, esp. if its your first one. Most marathon training programs are 16-24 weeks long. The more prepared you are, the more positive the experience will likely be.
Good luck whatever you decide.
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