Alhamdulillah,
Dear child, may Allah increase you in guidance and faith. It is praiseworthy that you are concerned about maintaining a strong connection with your religion at such a young age.
What you are experiencing is very normal, even for adults. Our faith and level of motivation can fluctuate due to various reasons like:
The whisperings of Shaytan, who tries to make us lose interest in acts of worship.
The temptations and distractions of the dunya (worldly life) that shift our focus away from the akhirah.
Boredom or lack of khushu' (heart's presence) in prayers due to habits forming.
Tiredness or lack of effort in reviving the heart's attachment to Allah.
However, these are tests from Allah to strengthen our iman. Here are some suggestions:
Renew your intention before every prayer, reminding yourself you are doing it solely for Allah's pleasure.
Ponder over the meanings of Quranic verses and duas during salah to focus your mind.
Seek inspiration by learning stories of the Prophets and how they turned to Allah sincerely.
Make dua to Allah to increase you in love and keenness for salah and Quran.
Join a study circle with like-minded friends to reignite your passion for Islam.
Never underestimate the smallest good deeds - consistency is beloved to Allah.
Remember, iman has its ups and downs for everyone. Don't be hard on yourself. Rejoice in the blessing that your heart is still inclined towards Allah. With patience, reflection and effort, your enthusiasm shall return InshaAllah.
You are in the beautiful age of nurturing your relationship with Allah. Keep fighting against any laziness and turn to Him wholeheartedly. May Allah accept your striving.
And Allah knows best!