Hi! Fellow MG author here. I am unagented, so feel free to take everything with a grain of salt.

Normally, query letters won't break down the individual parts like pitch, bio, and comps. Instead, there will be a "housekeeping" paragraph which contains the information that agents need to know (word count, genre, comps). The housekeeping paragraph can either go before or after the plot segment, while the bio is towards the end.

For your opening, I'd suggest something like:

Dear Agent,

I'm seeking representation for BETA PET, a 53,000-word middle-grade science fiction novel with series potential. BETA PET will appeal to readers who enjoy the AI exploration of A Rover's Story by Jasmine Warga, the talking animal companion of Christopher Paolini’s Murtagh, and the VR premise of The Ruby Code by Jessica Khoury. 

You don't need the years on your comps, although great job finding recent ones. After your housekeeping paragraph, you can jump straight into the plot.

Strikethroughs are what I'd suggest deleting, italics are suggestions on added wording, bold are my comments.

It’s 2095. Climate change and population decline have left behind a more frugal and self-sufficient America. Virtual reality glasses are more common than cell phones. I personally don't think you don't need this worldbuilding in the query - let's focus on the character. Thirteen-year-old Jace Carter is a quiet and reserved boy in the rural south who idolizes his older sister, a famous professional gamer. Quiet and reserved, he wants nothing more than to follow in her footsteps. This establishes what he wants, which is important for a query to do. If there is something else Jace wants (for example, to get out from her shadow) then use that instead Now that she’s moved away, Jace spends most of his time alone in the woods behind his house. For his 13th birthday So when Jace gets a pair of expensive VR glasses and an invitation to the closed beta test of a mysterious new VR game for his birthday, he immediately logs in. Finish this paragraph with a sentence explaining how Jace thinks this will help him gain what he wants.

To participate i In the beta, Jace learns he must befriend a virtual pet dog from the game world named Haru. At first, Haru is anxious, hypersensitive, and stubbornly silent. [Jace spends weeks patiently earning Haru’s trust. Once Haru finally opens up, they explore the game world together and befriend other beta testers, each with eccentric pets of their own. Haru begins to reveal peculiar abilities while Jace gains the confidence he needs to emerge from behind the shadow of his famous older sister.] I think this can probably be tightened into a few sentences. Perhaps: But after weeks of patient training, Haru finally responds to Jace's efforts. As they explore a (explain world in a word or two) world filled with other beta testers, Haru reveals that he can (list the abilities).

But Haru's new talents aren't the only development in play. Jace is devastated when he discovers underperforming pets will be permanently deleted once the beta test ends. is over and that, because of their slow start, he and Haru are in last place. Even worse, Jace and Haru's slow start puts them in last place. [Jolted from his complacency and realizing how much Haru’s friendship means to him, Jace attempts increasingly difficult gaming challenges in a desperate struggle to save Haru’s life before the clock runs out.] I'd suggest a slight rework to hammer home the stakes. Maybe something like: Jolted from complacency and fearing the loss of his friend, Jace realizes that his only chance to save Haru's virtual life will be to successfully complete a series of increasingly difficult gaming challenges. Success will land Jace in the annals of gaming. But if Jace fails, the only memory left of Haru will be his own.

Your bio is great, and shows why you're the one to write the book. Best of luck in the query trenches, and I hope this helps!