The odds I’m pregnant with twins??

So I found out at 11 dpo that I’m pregnant and I have taken several different types of tests with faint lines. I have four kiddos before this but last pregnancy was at 26 and now I’m 33. I couldn’t detect My other pregnancies till I was 15-17 dpo. I also never had implantation bleeding with any of my other pregnancies and did today where I am now 12 dpo today due for period tomorrow. today I noticed a very very light brownish spotting or like specs in underwear and a dot of it when I wiped. There were no clots it almost looked like CM mixed with color. I haven’t seen anymore since early today and it’s not like a period. Just curious if older age does increase chances of having twins as well as implantation bleeding?