Announcing pregnancy to family

I'm about 7 weeks pregnant with #2, I finally had a positive test last Tuesday! I've told 2 close friends and obviously my boyfriend. I want to tell my mum because I kept it from her untill 9 or 10 weeks with my first & I want to tell her how. I was thinking of writing an Easter card from my LG and putting 'p.s I'm gonna be a big sister!' But my boyfriend said 'I still think t's too early, we don't wanna get their hopes up if it doesn't happen' he's said stuff like this a few times I can't help but think he's hoping that will happen.. Anyone else's bf do this? It's upsetting because I'm a lot closer to my mum now and I want her to know 😔