Stocking up on baby things?

I<3Dolphins • I`m a 23 year old Military wife. My husband and I have been TTC #1 since November 13, 2013. ✨
I am trying to concieve and I have been for 10 months. Is it bad to get  baby things even though I'm not pregnant? 
​I was at the check out the other day with wipes and diapers and the guy asked how old my baby was and I told him I didn't have a baby. And he said, 'why do you need diapers and wipes if you don't have a baby?' It mad me a little mad. 
​Sorry about complaining. 
​Has anyone else not pregnant bought baby things?