You will likely be better off maxing out the 401k, HSA, and all other tax advantages first, unless you are saving up for something in the midterm.
Bonds are more for protecting money you have rather than growing money. They are not necessary when you first start. I would work on getting the total stock market fund above the $10,000 limit for admiral shares before anything else.
Looking at trailing performance is generally a bad idea. It is better to look at forward looking measures such as price to book ratio, price to earnings ratio, and price to dividend ratio which generally look more favorable outside the US. Additionally the dollar has been on an upswing since 2012 which accounts for a lot of US stocks better performance. Personally I would start adding international shortly after I crossed admiral shares in the US stocks but that is up to you. DON'T add it in the future after it starts to show good performance, the idea is to either buy low or buy continuously, but not high.
You should consider your marginal tax rate when you get around to bonds. Perhaps you will be better off with tax advantaged bonds. Also, is the purpose of the bond fund for safety or diversification? If it is safety you are ok with TBM. If for diversification, with only 10% in bonds you may as well get as much bang for your buck as possible by going either long term index or long term government bonds.