How realistic is this plan of mine? Too ambitious?

Hey everyone! I just recently started running more seriously in June. I downloaded and have a plan from the Runna app (I've seen that that's not the most liked or recommended app or program here, but I'm going to stick to it) for a half marathon, which is in October. I used to be a really strong runner, but not in over a decade. Last year in September I was about 280lbs. For context, I'm a male, 27, and 5'7" tall. I started swimming in November, with the idea of getting my weight down to a decent mark before I started running to make it easier on my joints and all that. I'm down to about 220-225lbs currently.

Anyways, my plan is to do this HM in October and then do a full in June of next year in Duluth, MN. I just ran a 5k in 29min 30seconds on Saturday, and my long run was Sunday which was 9 miles and I felt good doing that. Is this plan too ambitious in anyone's experience? Any thoughts to make the plan better?