Vietnam finalised Itinerary - feedback please!

Hello! I'm looking to travel to Vietnam for the last couple weeks of October since weather (apart from Central but I've read October can still be decent) and crowds are pretty good and that's when I have free time. Note that I am absolutely okay with the idea of running around and not really "relaxing", I like to be out and doing things and not resting in my hotel!

The only thing I'm still sceptical about is Ha Long Bay. IF I don't do Ha Long bay then I'll do 2 days Hue and 3 days Da Nang instead and push everything back up one day so I can get a full first day in Hue and potentially an extra day in Hoi An but I think I've planned it accordingly. Here it is:

1. Days 1–2 – Hanoi Old Quarter, food, coffee culture. Train Street early morning or late evening Hoan Kiem, Train Street, museums Recover from jet lag
2. Day 3 – Ninh Binh day tour Trang An / Tam Coc + Hoa Lu Back to Hanoi in the evening
3. Day 4 - Ha Long Bay
4. Day 5 - Come back from Ha Long bay late
5. Day 6 – Fly Hanoi → Hue arrive at 3:30 - spend half doing solo sights
6. Day 7 - Tour of Hue Get your guide full day.
7. Day 8 – Travel early and arrive by 12 to Da Nang via train, take the 2pm Da Nang + Hoi An Get your guide tour. Ask to be left at Hoi An at end of it and see Lanterns.
8. Day 9 - Coconut Forest, Hoi an Old town, Fujian Assembly Hall, Shops/Markets. Come back to Da Nang late.
9. Day 10 – Fly Da Nang → Ho Chi Minh City (Try to arrive at an early flight and spend the day walking around the city, exploring temples and palaces and buildings in the city)
10. Days 10–13 – Ho Chi Minh City War Remnants, Cu Chi Tunnels Day 11 - Mekong Delta day trip and Coconut village tour Day 12. Relax and explore
11. Day 13 - Back to Hanoi to stay during the day and any last minute purchases and stuff I want to take with me back home and anything I missed in Day 1-2
12. Day 14 – Departure back to Ireland

I'm super excited but also really nervous as this would be my first ever proper solo trip to Asia! Many thanks for any recommendations but I'm pretty happy with this list :)