使用了现在完成时 'have made up my mind' 强调决定的既定事实，'devote oneself to' 是表达投身于某事的地道短语。
Stepping into the gates of Xinyu No.1 Middle School, I was overwhelmed with tension. My junior high days were waving goodbye, while high school was reaching out to me. I couldn't help but reflect on how pleasant and perfect my junior high life had been. My mind kept replaying scenes of my older siblings during their high school years; their lives were arduous yet filled with unique joy.
Now, I am officially a high school student. I hadn't expected high school to be so exhausting and stressful. I was assigned to Class 1, Grade 10, which is known as the elite class in the school. I had assumed the atmosphere would be intensely competitive and saturated with a strong learning vibe, but surprisingly, I didn't feel that pressure at all.
The academic atmosphere in the class wasn't particularly intense. Classes were often a bit noisy. Since I sat in the back row, my view was obstructed, and it was difficult to hear the teacher clearly.
Although I couldn't resist asking classmates questions during class, my grades are not yet at the level I desire. However, I have made up my mind to devote myself fully to my studies.
It has been several days since the military training ended. In those brief three days, I learned the value of endurance and focus. Looking back, I felt both physically tired and mentally irritated. This experience is akin to daily studying, which can sometimes be monotonous and boring, causing one's mind to wander during class.
Gradually, I am starting to adapt to high school life, though full integration will take more time. I will strive to adjust to the pace of high school and fight for admission to my ideal university!
步入新余一中大门时，内心紧张得无以复加。初中时代正与我挥手告别，而高中生活正向我敞开怀抱。我不禁感叹，曾经的初中生活是多么愉快且完美。脑海中不断浮现出哥哥姐姐们读高中时的情景，他们的日子虽然辛苦，却也充满了独特的快乐。
如今，我也正式成为了一名高中生。未曾想，高中生活竟如此疲惫且紧张。我被分到了高一（1）班，这是一中公认的尖子班。我本以为这里的气氛会极度紧张，充斥着浓厚的学习氛围，然而身处其中，我却并未感受到预期的那种高压感。
班级里的学习氛围并不十分浓厚，平日里上课时常有些嘈杂。由于我坐在教室最后一排，视线受阻，听觉也受到影响，难以完全跟上课堂节奏。
尽管我上课时常忍不住向同学请教问题，目前成绩虽未达理想状态，但我已下定决心，必将全力以赴投入学习。
军训结束已有多日。在这短短三天的军训中，我学会了忍耐与专注。回忆那段时光，身体感到疲惫，心情感到烦躁，这种感觉恰似日常学习，偶尔显得枯燥乏味，让人在课堂上思绪飘远。
随着时间推移，我逐渐开始适应高中生活，但完全融入仍需时日。我将为适应高中节奏而努力，为考入理想的大学而奋斗！
"Let us march toward success with unyielding determination!"
"He told Max, I am never getting off again."
"Under his teacher's guidance, he became determined to overcome oversleeping."
"Those with unshakeable resolve reach wisdom; those with untrustworthy words fail in action."
"Always remember, your determination to succeed is more important than anything else."