At Lvl 13 take whichever talent you really want, Target Locked is a great take with the Lvl 4 and 7 talents, though Good To Go and Pew! Pew! Pew! Makes her slightly stronger in pilot mode.
If you can stay in Mech, take Target Locked, if you get out of Mech fairly often, take Pew! Pew! Pew! To get back in fast, and take Good To Go if they got hard engage as it'll increase your survival by a lot in Pilot Mode.

At Lvl 20 take Timing Attack for a good amount of more damage, and Ablative Armor if you struggle surviving in Mech Mode.

At Lvl 1 take Pro Moves if you got 1 or multiple "dedicated" healers, aka healers that have a lot of Single-Target Healing that can keep you up, Pro Moves is generally also good for longer fights. If you lack dedicated healing, or it's msotly small fights/duels that don't last long, take Liquid Cooling and more or less use it on CD.

This build is for those that wanna play D.Va in Pilot Mode

At Lvl 1 take whichever talent you give preference, my preference is Full Metal.

At Lvl 10 take whichever talent you see fit, if you're rarely in Mech Mode and want the most impactful ultimate for teamfights, I'd say Bunny Hop, nice AoE damage, a stun, and you're unstoppable, it's a great ultimate to create havoc with, take Micro Missiles for focused damage.

At Lvl 13 take Pew!Pew!Pew! if you want to deal a good amount of more damage with your laser in Pilot Mode, if you want to be able to do more and be more mobile, take Good To Go. Good To Go is overall the best option if you wanna mainly play in Pilot Mode.

At Lvl 16 take whichever you feel like, assuming you wanna play in Pilot Mode they don't matter too much.

At Lvl 20 take Headshot for A LOT of laser damage, it's now hitting much harder and is very much fatal.