festivalFête préférée

The first word of a title is capitalized

jJe suis une fille quei adoraite célébrer pleusiaeurs fêtestival en l'iInde car c'etaist notre culture.

So are proper nouns and the first word of a sentence

une fille (subject) adore = "qui", object relative pronoun => je suis une fille QUI adore

plusieurs festivalS (plural agreement)

A celebration having deep cultural or religious significance is called "une fête"; "un festival" is something lighter, usually a cultural event revolving around a theme like "un festival du film"

EN Inde, EN France, EN Chine, EN Espagne etc (without article)

It seems you still love celebrations, so I'd use the present tense

toutefois, maMa fête favorite festival est "holi" « Holi », la fête des couleurs.

I'd suppress "toutefois", since there is no big opposition/contradiction between this idea and the former sentence
Such celebrations are capitalized too => Holi

cChaque année, dau mois de mars, tout le monde se ressemble dans sles rues et se jetter des couleurs différentes l'un sur les 'autres.

"ses" rues would mean "Holi's streets"
tout le monde jETTE (third person singular)
"tout le monde" triggers a singular agreement (it's a group taken as a unit), so "l'un sur l'autre" would apply, lit. "one on another"

cCe festival est un symbole de l'adieu à l'hivers et aussi un gagnerla victoire sur les mauvaises choses. J'adoreee beaucoup cette fête ou festival vraiment cette fête.

Singular => hiver
"gagner" is a verb; "victoire" is a noun, it would be a good pick here
Space after a period
Verbs expressing a high degree of something (like "adorer") are modified using "vraiment", "réellement" or such adverbs