4 days to get Ghibli Museum tickets?

We are planning on buying our Ghibli tickets at Lawson when we arrive tokyo. Is alright to buy them 4 to 5 days before? I'm thinking of asking the hotel to get some for us, but im embarrassed to ask. I read that it could get fully booked.

Generally speaking it is alright on regular weekdays outside of school holidays. And it is not alright on weekends, public holidays and the spring (mid March to early April), summer (mid July through August) and winter holidays (late December to early January).

Ok. Our trip is in June 15-22.

You can try purchasing the tickets from the followings:

https://www.govoyagin.com/activities/get-tickets-for-the-ghibli-museum...

http://www.bridge.jpn.com/contact-tickets
You have to pay a service/handling charges (600 yen for first ticket and 300 yen for subsequent tickets), postage and PayPal service fee 4%.

I booked both Ghibli and Fujiko F Fujio museum tickets through Bridge JPN for June 12-13 and they will mail it to my hotel. V. excited!

JTB agency (Asia - HK, Taiwan & Korea, USA, Europe)
JTB Singapore only sell the tickets to you with the condition that you book the hotel from them (min. 1 nite stay). Cost is S$19 for Adult and S$15-S$11 for child depending on age.

Thanks Kitty! I'm all set. The hotel I'm staying at has purchased the tickets for me. I'm so thankful for that.