How can I invite my irreligious family to the faith when I am the youngest member of the family?

The first thing one who calls to Allah is advised to do is to be sincere to Allah, to deal honestly with Him, to seek His help – Glorified be He – and to supplicate Him to guide that family and open their hearts to the truth, while inviting them with wisdom and good counsel, and explaining that young age should not be an impediment to accepting the truth.

The caller to Allah must be gentle, soft, respectful, and endearing in speech. Their conduct and adherence to the truth should be a good example. Furthermore, indirect methods of da'wah should be employed, such as gifting brochures and booklets, guiding them to beneficial websites and lessons, and seeking help from elder and committed individuals.