While in English we use the perfect tenses after 'to be the first/second/etc. time that', in Spanish the present simple is used for the present, while the past imperfecto or indefinido are used for the past, depending on the usual factors that affect their choice; the subjunctive is the normal choice for the future. [See also: Subjunctive in relative clauses]

-Es la primera vez que hago algo así — It's the first time I've done anything like this

 

-Era la primera vez que hacía algo así — It was the first time I had done anything like that [Seen as ongoing]

→Fue la primera vez que hice algo así — It was the first time I had done/did anything like that [Seen as completed]

 

-Será la primera vez que haga algo así — It'll be the first time I've done anything like that / It'll be my first time doing anything like that

 

-Es la última vez que hago algo así — It's the last time I do anything like that [Same as Spanish]

-La última vez que estuve aquí/hice algo así, tenía quince años — The last time I was here/ I did anything like that, I was fifteen ['La última vez que' is followed by the preterite (indefinido)]