They get there in their own time, DC one ate like a total champ from the off. DC 2 (18 months old now) frankly didn't give a shit about food and only liked junk stuff but it's like someone flicked a switch about a month ago, so now when I call "dinner time" she races her big brother to the table. To put it into perspective she is a whole YEAR older than your DC and has only just got motivated to eat three times a day.
Just some thoughts from above:
You don't HAVE to offer solids all the time this young: You said your DC is coldy - it's fine to sack off solids altogether for a few days, that baby is going to want milk and comfort. In fact, with my second DC who is 18 months, I still skip meals if she's too tired or whatever, she gets to graze at other times
Batch cook veg etc: I usually steam / boil enough pasta / carrots / broccoli/ cauliflower whatever to feed the DC for 2-3 days so always have stuff on standby for the hectic days when cooking is hard to fit in.
Limit your range: it's OK not to try loads of stuff at once, you'll find it hard to maintain, as someone already said, they can eat the same few meals over and over.
Take shortcuts: it's OK to use jars and pouches and a personal favourite of mine is frozen mash and frozen baked potatoes (frozen veg in general).
Oh yes, and don't believe what other people you know claim about how much their kids put away, for various reasons, not everyone is being entirely truthful, so take a hefty pinch of salt (see also sleep....)
PS. You're being hard on yourself, you're not failing. It's just bloody hard being a parent to a small baby. And just when you think you've cracked something the little blighters change the game.