I think you all missed his question, he is flying on a sim first. No reason to stick to calm conditions on a sim, that's what a sim is for, improving your skills. You can't improve if you don't test your limits. By the way, 10kts is a little over 12mph and you should be perfectly capable of handling the Lt-40 in 12mph winds if you can handle the sim at 15mph or more.

By all means, when you get around to flying the real Lt-40, start with calmer conditions and preferably with an instructor. But if you're doing fine on the sim, don't be afraid of 5 to 10mph winds after your first couple of solos.