No problem. There's really no way to avoid touching a PCB (motherboard, RAM, GPU, PCI-e card, etc) when you're building or working on a computer. Just remember to work with clean hands, avoid static by wearing a grounding strap or periodically touch a metal part of the case if the PSU is connected, and never let anything metallic bridge any contacts or exposed PCB components. Dropping screws or screwdrivers anywhere in a PC case is to be avoided...bad things can happen.