Is it okay to make personal dua right before you say the Salaam?

Assalamu alaikum everyone. I was praying Maghrib today and had a really heavy thought on my heart, so right before I finished, I made a quick dua. It just felt like the right moment, right before saying 'as-salamu alaykum'. Is this allowed? I've always heard that the best times for dua are during sujood or after the tashahhud, but I wasn't sure if making a personal request this late in the prayer is correct. Does anyone know the ruling on this?