Response
It depends on what age she was when the alleged crime was committed. If the girl admits that there was any activity, then you can be charged. Otherwise , it is not easy. Moreover, before he makes up any complaint against you, you can also make allegations against him for various reasons that I would tell you if you contact me. This move will make his case weaker if he tries to make any against you.
The girl, as told by you, is still very young and, naturally, can be persuaded into going against you while filing the complaint. My advice to you would be to go no further in this relationship. The question regarding the allegation of sexual nature made against you by her uncle would be hard to establish. First of all, she is a minor and, if any fir lodged against you, the defence of consent is not applicable.
As you have an intuition that her uncle may implicate you in a false case, you do one thing: approach the police station in your area with a complaint letter. Even for a false case under POCSO, there has to be some nexus. It seems the police must have applied section 8 or 10 of the POCSO act. In the event you are not able to procure a FIR from the police, approach some lawyer. He can get a copy of the FIR from the court, as a copy of every FIR is sent to the concerned magistrate.
Reference: POSCO act – 202100499-20210042-2912
LAW5636
LAWAYZ-2023-41