Upvote:3
There are no hard and fast rules, you have to convince the consulate that you meet all the requirements and, specifically, that you have sufficient financial means for your trip and that you will leave the Schengen area at the end of the stay.
Being unemployed is a disadvantage on both counts, because it means you have no income to fund the trip and no situation to return to so that you could be tempted to take any opportunity to remain in the Schengen area, even illegally.
There are still other things you could produce to alleviate those concerns, like proof that you registered for university or have money on your bank account but you have to realise you don't have the most favourable profile and a refusal is a very real possibility in any case.