Updated after latest hint:
Are you a
SPACE (character)?
I'm found in a gong,
The second character in the string "a gong" is a space. Gong would be a distractor in this case, as it could be literally any word.
I look the same from both ends.
A space is blank; it looks the same (empty) from all directions.
Now don't get me wrong (ignored)
Two straight and three bends.
In capital letters, AE are all straight lines (two straight) while SPC all have curves (three bends).
I'm a form of a word,
But not the one you're used to.
Could mean a couple of things; spaces define words by being the borders, or in computer science, each character (including "space") can be represented by a "word" or set of bits.
You know, I'm my third,
The third character in "my third" is also a space.
You'll find me if you choose to (ignored).
Original try below...
Are you a
Tone?
I'm found in a gong,
When you hit a gong, a tone is played.
I look the same from both ends.
Tones are periodic, so when plotted as a function of time they look the same forward and backward.
Now don't get me wrong (ignored)
Two straight and three bends.
Depending on the font/handwriting, "t" is written with two straight lines, and "one" can each be written as a single curved line.
I'm a form of a word,
Tonal languages use tone to convey meaning
But not the one you're used to.
English isn't a tonal language, and English-language speakers find tonal languages difficult to learn and understand.
You know, I'm my third,
In music, "tone" is another word for a diminished third interval.
You'll find me if you choose to (ignored).