A little background, we are both in our late 20s, living together for a little under 1 year, and dated for 1 1/2 yrs, we are a multi-racial couple with my fiance being Vietnamese. We got engaged on Thanksgiving and announced it to my parents and close family then as well. We have yet to announce it to his family. I am letting my fiance take the lead on that and recently asked him about when we should tell them. He said on New Year's. I prompted him a little with, " this New Year's weekend or Chinese New Year?" I don't feel that I want to push the issue, but also do want to start the planning and get an idea for guest lists and budget. I need to talk to him specifically about those reasons for announcing. Is there anything I may be missing culturally though (announcing at a certain time, etc.)?

PAIF/SAIF welcome
TTC #1 since 10/2010, Cycle #26
Diagnosis: Unexplained IF
IUI #1 (Cycle #24): Clomid, Gonal-F, trigger, 4M post-wash = BFN 11/9/12
IUI #2 (Cycle #25): same protocol, 10M post-wash = BFN 12/12/12
Break Cycle #26 = CD69 BFP
Beta #1 2/20/13 = 449, Beta #2 2/22/13 = 1012, Beta #3 2/25/13 = 2479
u/s 3/1/13 = gest sac and yolk sac
Re: Announcing our engagement to his family
OR, the two of you can stage a surprise re-enactment for them! Be honest with them, tell them that something happened that you want to tell them about, but tell them you want to SHOW them...then reenact it. I think that could be very special to them. Surprising and special.
Good luck! and congrats.
I could of course, be wrong as many people celebrate differently.
My Chinese-American fiance called his family to tell them within moments of us getting back within cell phone range (he proprosed on top of a mountain).
I would consider it a huge red flag to not want to tell one's parents they are engaged. It's a huge deal and assuming a healthy - or even not healthy - relationship, most people want to tell their family when something so big happens. Is he hiding something from them? Perhaps they know something about him that you don't.
You do have cultures to consider - his family may be expecting to pay for a Chinese reception including all their friends and you may be thinking 300 people neither of you know is not ideal.
Good luck either way!
The two of you need to have a conversation about this. If you aren't comfortable talking to him about annoucing your engagement to his family, you probably need to think about some pre-wedding counselling soon.
This is definately a time for open, honest, communication, without pointing a finger, blaming or getting upset.
If he hasn't told them yet, it is definately your right to know why. Perhaps he's afraid of their reaction, or perhaps he doesn't think that telling them is as important as you think it is... who knows really! Inter-racial/cultural relationships can bring these sorts of problems. I know that in my case, there was definately a bit of fear in telling everyone in my family because (very sadly) some of my familiy members (not immediate family) are pretty southern and racist.
At any rate, keep calm and push for an honest answer, while maintaining your cool. Learning to communicate calmly and honestly is one of the best things you can do for your relationship.
PAIF/SAIF welcome
TTC #1 since 10/2010, Cycle #26
Diagnosis: Unexplained IF
IUI #1 (Cycle #24): Clomid, Gonal-F, trigger, 4M post-wash = BFN 11/9/12
IUI #2 (Cycle #25): same protocol, 10M post-wash = BFN 12/12/12
Break Cycle #26 = CD69 BFP
Beta #1 2/20/13 = 449, Beta #2 2/22/13 = 1012, Beta #3 2/25/13 = 2479
u/s 3/1/13 = gest sac and yolk sac