How to get pregnant?

Currently trying to get pregnant. Last month we had no luck. Im worried that because of my age 35yrs that it will be hard to get pregnant. I have two girls 4 & 8 they keep asking for a baby brother or sister. I waited this long do to grad school and now that i am about to be done i am ready. Any moms in here that had a baby after the age of 35? how long did it took you to get pregnant? i need some hope i feel that if i am not able to conceive i will be devastated because i always wanted a big family. Now i regret waiting this long hearing how after the age 35 fertility goes down😓