I have transferred to a new school starting from today.

Now, I have still missed the rest of my class's students a little.

A second grade of boy gave me a cute small and cute flower bouquet.

It's a bit bittersweet to leave my present school.

New school starting (from) today

"from" is optional

Finally, it startthe first day of April has started.

I transfer to a new school from today.

Now, I have still missed the rest of my class studentmates a little.

A second grade ofophomore boy gave me a cute small flower bouquet.

The "second grade" usually refers to primary school, while "sophomore" refers to the second grade of any school. Where I'm from, though, if it's the second grade of high school, then we much more commonly say "ninth grade." It depends on the school system of the area.

Someone gave me a rose petals for a bubble bath, a handkerchief, canned cookies, a water bottle etc.

It's a bit bittersweet to leave my present school.

But I should change my mindset.

New shool studentclassmates are waiting me.

New sSchool fFrom tToday On.

Finally, it startthe first day of April. has arrived.

I transfer to a new school from today on.

From today on is a short form of "From today onward" which basically means 今日から

Now I have still missed the rest of my class students a little.feel almost nostalgic for the friends I've made along the way at my soon to be previous school.

A sSecond grade ofyear High school boy gave me a cute small flower bouquet.

"Second Grade" は小学校の学生感じ。

Someonand then someone else gave me a rose for bubble bath, handkerchief, canned cookies, water bottle , among other cute presentsetc.

It's a bit bittersweet, having to leave presentthis school.

But I shouldcan't change my mind.

New shool studentskids at a new school are waiting me.!

New school fromstarting today

Finally, it startwas the first day of April.

I transferred to a new school from today.

Now I haveI still missed the rest of my classformer students a little.

A second grade of boy gave me a cute small flower bouquet.

or "A boy from second grade"

Someone gave me a rose for bubble baths, handkerchief, canned cookies, water bottle etc.

It's a bit bittersweet to leave presentthis school.

But I should change my mind.look on the bright side

The sentence is grammatically correct but a bit unnatural

New shool students are waiting me.

New school fromstarting today

more natural

Finally, it startIt's finally the first day of April.

"The first day of April has finally arrived." is another way you could say this.

I transfer to a new school from today.

OR Starting today, I'm transferring to a new school.

Now I haveI still missed the rest of my class studentstudents of my former class a little.

A second grade of boy gave me a cute small flower bouquet.

SomeoneOthers gave me a roses for a bubble bath, a handkerchief, canned cookies, and a water bottle, etc.

It's a bit bittersweet to leave my present school.

But I should change my mind.attitude.

fits a little better with what you're trying to express

New shool studentsThe students at my new school are waiting me.

New school from today

In Japanese, it's normal to say 今日から/"from today", but in English I think it's more natural to say "today" (without "from"/から) or "starting today."

Finally, it startIt's finally the first day of April.

I'm transferring to a new school from today.

Now I haveI still missed the rest of my class my former students a little.

A boy in second grade of boy gave me a cute small flower bouquet.

Someone gave me a rose for bubble bath,I also got rose bath powder, a handkerchief, canned cookies, a water bottle, etc.

It's a bit bittersweet to leave my present school.

But I should change my mindmove on.

move on（気持ちを切り替えて）前に進む
move on は「前に進む」というニュアンスの英語表現です。

New shoolThe students at my new school are waiting for me.