No because 70 is the current level cap, and you'd need a lot of EXP to level her up. The pet has to level up in your care either through battling or missions.
for example, say I was user level 10 and bought a level 25 pet. I send them on a mission overnight, and they level up to 26. Once they come back from the mission, my user level is now 26 because the pet levelled up after I sent them on a mission.

So if the level 70 pet goes on a mission and comes back level 71 then i go from level 24 to 25?

sorry is im asking too many questions~

No, it's alright. That is correct in part - your level will change based on the highest level pet you've leveled up yourself (missions). currently Esmeralda is the highest level pet you can level up, as your lvl 70 kelpari cannot level up past 70.

Hiraeth preaty mutch answered the question about the level, i do have a small thing to add tho : using xp orb on the pet to make it level up should be also be a way to level yourself up, if you have a couple of those laying around it can quicken the leveling up process. ^-^

edit :
oh, and your nixi is all in intelligence so you want to send het into the second mission for better reward and exp ^-^

i found a few earlyer today, not sure if you can use the level 9 on her (probably not) but it can be usefull when training new members.

yes, of course tho most of them may not be avalable/affordable to you yet. At the moment you have the broaker you can go to if you are looking for specific equipement, you can get some realy good gears from missions satchels, there are sone you can buy some at the second town market and realy but realy later, you can craft stoneweaver gears from the LG after unlocking the recepies (that one is a loot with extra steps but it's worth it) ^-^