Even amongst those who believe in reincarnation, there is not the unanimity that we might expect. Who is to say that time moves forward in a nice straight line? Certainly the consensus, amongst many scientists and philosophers alike, is that this is not so. Time may well turn out to stand still while we move through it or even, perhaps, to go backwards. If that's the case, our next reincarnation might be in the past, not the future! Stick, with what you are sure of. Make the most of what's real, right now.
Why are things as they are? How have they got this way? Shouldn't they be different? You have the power and the chance to create change. Life allows you to ring in the new, but before you alter everything you may just want to think a little harder about what was so wrong with the old. It is always easier to find fault with something that already exists. If an idea has not yet been explored it is so much easier to imagine that it offers a perfect solution.