What he said- unless you've measured or calculated the heat loss of the structure it's impossible to say for sure if it'll keep up. If the glazed area isn't outrageous, the foundation is insulated, and there's something better than cheez-whiz & R-11 batts in the 2x4 cavities, odds are your design-day heat load isn't over 50K on a house that size in Anchorage. But I'm sure there are exceptions to prove the rule...
"properly insulated" isn't a specification, and 2x4" construction is a bit on the thin side for that climate unless there's extensive use of insulating foam sheathing or the cavities are filled with 2lb density closed-cell foam, etc. But if it's tight and not over-glazed, even with R13 batts or similar & no insulating sheathing it could still be well under the ~70-75K full-fire output of the thing at an outdoor design temp of -15F or whatever you typically need. (Boilers need to be sized for the peak heat load- the average outdoor temp of 10F means little when it's 25-30 degrees cooler than that and you want to stay cozy.)
If you need the full 75K, and the radiation needs to run at 180F to get that much into the space it could be marginal, since the boiler's output will be ~65K with 160F+ return water from radiation- it'll be well out of the condensing region and running at best ~85% efficiency. "high output" baseboard is also not a spec- no telling what that really means relative to your heat load and operating temperatures. Let's say it's specified at 750BTUs/foot at 180F- your 100' of baseboard still won't deliver that 75K because it'll never achieve that for an average temp if driven by a boiler that's maxing out at ~65K at those temps. But it can easily deliver ~50K to the room at 150-ish temps, and the boiler would clearly keep up, and run a higher (if still not condensing) efficiency. What your actual peak temps & BTU-delivery can be with the radiation & boiler you have requires a more detailed analysis, well beyond what can/should be done in web-forum.
But it all starts with calculation of what the real heat load is. From that and the baseboard specs you can determine what water temps the radiation will need to support that heat load, then you have to verify that the boiler can supply the requisite BTUs at that temp. You're probably good, but...