The Messenger of Allah ﷺ as saying: Sacrifice only a full-grown animal unless it is difficult for you, in which case sacrifice a lamb. (Using translation from Abū Dāʾūd 2797)
قَالَ رَسُولُ اللهِ ﷺ لَا تَذْبَحُوا إِلَّا مُسِنَّةً إِلَّا أَنْ يَعْسَرَ عَلَيْكُمْ فَتَذْبَحُوا جَذَعَةً مِنَ الضَّأْنِ