Sponge didn't rise!

I baked a Victoria Sponge Cake yesterday for the first time in about a year, and it didn't rise much, and I can't figure why.  I used my mum's gas oven, which I am not familiar with, and there is a chance I didn't let it heat enough before sticking the cake in, but I wondered if you guys had any tips for next time?  My initial thought is to add some baking soda, but I don't want to effect the flavour.  Luckily it tasted really nice, but it just wasn't fluffy enough!

Vicky

Definitely check the dates on any flour or baking powder you used and also how long have they been opened.  That or the weather could have impacted it as well.  Humidity can impact baked goods.