Yes that's right. De Rossi doesn't have much experience in coaching, let alone coaching a big team like As Roma. Imo, De Rossi was only made temporary coach by AS Roma, AS Roma will look for a coach who has experience in domestic leagues and inter-European leagues.
Indeed, the contract is until June this year. However, if his ability is good enough and he can improve the team very well and consistently, this doesn't close the possibility to extend the contract based on evaluation. I am sure that Rossi won't waste this opportunity to do his best in Roma. Although many people still doubt his ability because he is still lack of experience. At least, his existence of being temporary coach here in Roma can really give him a very valuable experience and also challenge. This is probably one of the reasons why he accepts the offer without concerning about the salary. But for sue, this path won't be easy for Rossi because Roma performance has really decreased and he must rebuild it consistently.