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It really depends on how dark your natural level is and how light you want to go. If you are chocolate brown, then getting you blonde really shouldn't be a problem since you have never colored your hair. Right now your hair is considered "virgin," in the areas it has not been lightened. Unless your previous highlights have been cut off completely, those areas may end up with a little damage if you do an all over lightening. Being careful enough to not cross over onto the previous highlights, with an all over lightening, is unrealistic. The damage though should be minimal, since your highlights were done over a year ago. If the old highlights are at the very ends of your hair, they should be easy to cut off should damage occur.

Your length now is another factor on if damage will occur. If it has been a long time since you have had a haircut, your ends are already damaged and putting chemicals on them will damage them further. If you are nervous about this, I would recommend not doing an all over. Instead I recommend a heavy highlight, getting a GOOD haircut to remove the damaged ends from your hair, and a deep conditioner before and after your highlights. This will prevent your hair from breakage NOW and after the highlights. Curly hair is naturally dry and brittle, and prone to breakage. Its the genetics of the hair. As long as you are not going too far away from your natural hair color, the damage should be minimal.

Also, do not let her put you under the dryer unless the manufacturers instructions on the lightener say it is ok to use heat. Go in for a consultation with the stylist BEFORE you make an appointment and ask her what kind of lightener she uses, what she thinks will look best, and if the blonde you want will work on your hair. You can research what lightener she uses by googling " (insert the lightener she uses here) and heat," after you leave. By searching for that you should be able to find out if its allowed by the manufacturers instructions. Once you have finished the consultation, either make an appointment (and cancel in advance if you change your mind) or take the stylists card and hours and book an appointment once you have researched. Most damage from lightener occurs by heat under the dryer. Most lighteners have an automatic time that they lose effectiveness and quit processing. Universal time is around 55-65 minutes at room temperature, or when it dries out. In a foil, the lightener will not dry out, especially in a dryer. OR if she sticks you under the dryer, watch the clock. If you have been under there for 10-15 minutes, lift up the hood. If she/he asks why you took it off, tell her that you are hot, and can't take the heat any longer. just a little white lie ;)

Last thing, if you are hispanic, it is VERY VERY difficult to get your hair above the orange stage. You may have to stop with it orange, have it toned, and then have a second process done in 1-2 weeks. If coarse Hispanic hair that gets stuck in the orange stage, is lifted from dark to light blonde in one sitting, it can result in a lot of damage. I have found that fine Hispanic hair, does not have problems lifting past the orange stage. Good luck and I hope this helps, sorry this was long!

I have mixed hair as well and I've dyed it burgundy a few times over the past two weeks. I regret ever doing it now because its extremely damaged and dry and at least five inches have broken off.