MB, I was baptised and confirmed at age 11 and I recall the clothing was not important. Even for babies now wearing white is traditional but not 'compulsory'. There's a part in the baptism service where a white shawl/stole is placed on the person but that's it for the white. I know a lot of ppl make a big fussy dress spectacle out of First Communion but in my mind that's not what it's about either.

I think you should just wear what you feel well dressed in and don't worry about the 'white' aspect. Also, the Easter Vigil is a pretty big spectacular event (and usually quite late in the evening) so if you're not comfortable with that, speak to your priest about doing it another time.

BTW, found a fantastic Saint's database here.