Grandma is having a baby?

I'm 25 and have a 2 year old. My mum is 44 and pregnant with her 5th child.. I'm really happy for her because I know she really wants this baby which is great, I just don't know how I feel about this.

My child will be 3 when her uncle/aunt is born.

Also, I'm concerned about her being pregnant at this stage in her life, aren't there more complications involved? Like downsyndrome? All 4 of her pregnancies have been great, no complications, all natural births and healthy weights.

Does anyone have any similar experience or advice please? Feeling a little lost.

Thank you in advance xx